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THE    PROBLEMS 

OF    PHYSIOLOGICAL   AND 

PATHOLOGICAL  CHEMISTRY 

OF  METABOLISM 

FOR  STUDENTS,  PHYSICIANS, 
BIOLOGISTS  AND  CHEMISTS 


BY 

DR.  OTTO  VON  FÜRTH 

PROFESSOR  EXTRAORDINARY  OF  APPLIED  MEDICAL  CHEMISTRY  IN  THE  UNIVERSITY  OF  VIENNA 


AUTHORIZED  TRANSLATION  BY 
ALLEN  J.  SMITH 

PROFESSOR  OF  PATHOLOGY  AND  OF  COMPARATIVE  PATUOLOGY  IN  THE 
UNIVERSITY  OF  PENNSYLVANIA 


PHILADELPHIA  AND  LONDON 
J.  B.  LIPPINCOTT  COMPANY 


COPYRIGHT,    1916 
BY  J.B.  LIPPINCOTT   COMPANY 


Eleclrotyped  and  prir.tedby  J.  B.  Lippincotl  Company 
The  Washington  Squart  Press,  Philadelphia,  U.  S,  A. 


AUTHOR'S  PREFACE 

In  overseeing  the  corrections  incident  to  the  publication 
of  the  volume  herewith  presented,  the  author  has  been  for- 
tunate in  having  the  assistance  of  Dr.  Carl  Schwarz,  Docent 
in  Physiology  in  the  University  of  Vienna,  and  of  Dr.  Adolf 
Fuchs,  Assistant  in  the  Royal  and  Imperial  Franz  Joseph 
Hospital.  It  is  a  pleasure  to  acknowledge  here  to  both  these 
gentlemen  the  author's  most  cordial  appreciation.  Nor 
can  the  author  fail  to  express  his  obligations  to  Mr.  F. 
Lampe- Vischer,  head  of  the  F.  C.  Vogel  Publishing  Com- 
pany of  Leipzig,  for  the  readiness  of  cooperation  which  he 
invariably  accorded,  at  every  stage  of  the  preparation  and 
publication  of  this  work. 


TRANSLATOR'S  PREFACE 

The  wide  and  cordial  appreciation  with  which  von 
Fürth  's  ' '  Problems ' '  has  been  met,  not  alone  by  his  students 
and  clinicians,  but  by  technical  scientists  in  physiology  and 
in  pathology  as  well,  is  ample  reason  for  its  presentation  in 
translated  form.  The  book  is  based  upon,  and  in  the  orig- 
inal text  is  cast  in  the  form  of  twenty-five  lectures  addressed 
to  students  of  biological  chemistry,  and  has  as  its  purpose 
the  presentation  of  the  subject  of  normal  and  pathological 
metabolic  chemistry  as  a  broad  and  connected  whole.  As  a 
well-prepared  and  enthusiastic  guide,  thoroughly  conversant 
with  the  topography,  history,  popular  activities,  spirit  and 
ambitions  of  the  land  through  which  he  is  conducting  a  group 
of  thoughtful  travellers,  seeks  to  point  out  the  salient 
features  of  the  landscape  and  the  accomplishments  of  the 
people,  their  successes  and  their  needs,  and  thus  in  the  end 
leaves  in  the  minds  of  the  group  before  him  a  well-balanced 
idea  of  the  region,  so  our  author  seeks  to  guide  his  readers 
through  the  living  body,  following  the  ingestion  of  the  great 
types  of  food,  their  digestion  and  absorption,  pointing  out 
here  and  there  in  the  unknown  field  of  intermediate  metab- 
olism the  little  which  has  become  known,  indicating  their 
resultants,  marking  the  points  of  departure  of  disease,  pre- 
senting the  big  facts  which  we  know  in  connection  with  the 
metabolic  affections,  and  at  all  times  suggesting  the  possibil- 
ities of  further  investigation  and  of  orienting  our  thoughts 
into  conformity  with  the  general  plan  of  nature's  chemical 
performances.  The  book  is  thus  rather  a  guide  to  thought 
than  to  the  technicalities  of  the  laboratory,  and  in  this  ap- 
peals alike  to  students,  chemists,  biologists  and  physicians. 
It  is  in  no  sense  a  compendium,  nor  is  it  a  book  of  reference 
for  details,  technical  or  otherwise ;  but  is  a  presentation  of 
the  well-ordered  thought  of  a  master  of  biochemistry,  the 


vi  TRANSLATOR'S  PREFACE 

result  of  well-considered  culling  of  facts  and  their  align- 
ment in  probable  sequence.  A  satisfying  series  of  page- 
references  serves  to  direct  the  reader  to  the  literature  in 
which  are  recorded  the  minutiae  of  details  which  such  a  work 
cannot  reasonably  be  expected  to  embody. 

In  the  three  years  since  the  appearance  of  the  original 
edition  there  have,  it  is  true,  appeared  in  current  literature 
facts  which  the  author  would  doubtless  have  noted  had  the 
times  been  more  fortunate ;  but  the  translator  has  felt  that 
the  book  is  so  peculiarly  one  man's  own  that  to  annotate 
would  be  meddlesome  and  intolerable.  The  possible  changes 
in  statement  at  any  rate  would  have  been  no  more  than  minor, 
and  the  additions,  mainly  in  connection  with  the  sections 
dealing  with  proteins  and  diabetes,  would  surely  not 
materially  modify  the  general  picture  which  the  author  has 
drawn. 

In  the  original  German  edition  Professor  von  Fürth 's 
"Probleme  der  Physiologischen  und  Pathologischen 
Chemie"  appeared  in  two  separately  complete  volumes;  a 
translation  of  the  second  of  which,  dealing  with  the  chem- 
istry of  normal  and  pathological  metabolism,  appears  in  the 
following  pages.  The  first  volume  of  the  series  deals  with 
and  is  entitled  ' '  Chemistry  of  Tissues ' ' ;  reference  to  which 
from  place  to  place  appears  in  the  following  text.  The  trans- 
lator can  only  regret  that  the  conditions  of  publication  have 
permitted  of  the  presentation  of  no  more  than  a  single  one 
of  these ;  but  it  should  be  clearly  understood  that  the  com- 
pleteness of  the  present  volume  is  in  no  sense  involved  by 
the  fact  that  its  companion  volume  remains  untranslated. 

The  translator  has  endeavored  to  preserve  the  spirit  of 
the  book,  but  has  not  attempted  to  maintain  an  absolutely 
literal  translation.  Doubtless  defects  of  form  and  perhaps, 
unfortunately,  of  sense  as  well,  may  be  detected  in  the  trans- 
lation ;  if  so  no  one  will  regret  them  more  than  the  translator. 
But  these  aside,  he  can  and  does  frankly  commend  the  book 
as  an  orderly  and  masterful  delineation  of  the  important 


TRANSLATOR'S  PREFACE  vii 

features  in  the  plan  of  chemical  function  in  the  animal 
economy.  To  the  publishers  he  would  here  express  his  ap- 
preciation of  their  unfailing  kindness  and  consideration  in 
spite  of  many  annoying  delays  in  the  preparation  of  the 
material  for  publication,  arising  from  the  pressure  of  de- 
mands in  other  lines  which  at  the  time  seemed  insistent. 

A.  J.  S. 


CONTENTS 


CHAPTER  PAGE 

I.  Introduction  to  the  Study  of  Metabolism.    Protein  Digestion 

in  the  Stomach 1 

Introduction.  Protein  Digestion  in  the  Stomach.  "Mock  Meal" 
and  Pawlow's  Ventriculus.  Nervous  Mechanism  of  Secretion. 
Action  of  Psychic  Influences.  Excito-secretory  Stimuli.  Gastric 
Secretin.  Inhibition  of  Secretion.  Origin  of  Free  Hydrochloric 
Acid  in  Gastric  Mucous  Membrane.  Physico-chemical  Explana- 
tions. Acid-production  by  Marine  Snails.  Determination  of 
Acidity  of  Gastric  Juice.  Binding  of  Hydrochloric  Acid  by  Proteins. 
Extent  of  Protein  Digestion  in  the  Stomach.  Comparative  Physio- 
logical Considerations.  Efforts  to  Isolate  Pepsin.  Methods  of 
Pepsin  Determination.  Law  of  Pepsin  Fermentation.  Propepsin. 
Pseudopepsin.  Passage  of  Pepsin  into  Intestine.  Resistance  of 
Stomach  to  Autodigestion.  Origin  of  Round  Ulcer  of  the  Stomach. 
Chymosin.  Ultramicroscopic  Studies  of  Lab-process.  Association 
of  Bacteria  in  Lab-process.  Plastins.  Question  of  the  Identity 
of  Pepsin  and  Rennin. 

II.  The  Proteolytic  Pancreatic  Ferment 33 

Transfer  of  Food  from  Stomach  into  the  Intestine.  Passage  of 
Intestinal  Contents  into  the  Stomach.  Pancreatic  Fistulas. 
Secretin.  Secretin  and  Cholin  and  the  Vasodilatins.  Entero- 
kinase.  Activation  of  Trypsinogen  by  Calcium  Salts,  etc.  Indi- 
viduality of  Trypsin.  Conversion  of  Trypsin  into  Zymoid. 
Action  of  Trypsin  on  Polypeptids.  Adaptation  of  the  Pancreatic 
Secretion  to  the  Food.  Quantitative  Determination  and  Ferment 
Law  of  Trypsin.    Toxicity  of  Parenterally  Introduced  Trypsin. 

III.  Protein-Digestion  in  the  Intestine 50 

Erepsin.  Extent  of  Protein  Dissociation  in  the  Intestine.  Passage 
of  True  Proteins  and  High-Molecular  Protein-Derivatives  into 
the  Blood.  Resorption  of  Iodized  Proteins.  Objections  to  the 
Resorption  of  Albumoses  and  Aminoacids.  Residual  Nitrogen. 
Synthesis  of  Digestive  Products.  Parenteral  Introduction  cf 
Protein.  Protein  Synthesis  from  Advanced  Cleavage  of  Protein. 
Abderhalden^  Experiments.  Application  of  these  Results  in 
Sickroom  Dietary.  Relation  of  Amides  in  Metabolism  in  Vege- 
tarians. Protein  Synthesis  from  Ammonium  Salts.  London's 
Studies.    Summary. 

IV.  Proteolytic  and  Peptolytic  Tissue  Ferments 75 

Autolysis  a  Complex  Process.  Antiseptic  Difficulties  in  Autolysis 
Experiments.  Is  Autolysis  the  Continuation  of  an  Intravital 
Process?  Deamidizing  Tissue  Ferments.  Importance  of  Auto- 
lysis in  Various  Pathological  Processes.  Autolysis  and  the  Re- 
gressive Changes  in  the  Living  Body.  Relation  to  Bacterial  Proc- 
esses. Proteolytic  Ferments  of  Leucocytic  Origin.  Effect  of  Ex- 
trinsic Factors  upon  Autolysis.  Abderhalden^  Investigations 
upon  Proteolytic  Tissue  Ferments.  Detection  of  Proteolytic 
Tissue  Ferments  by  Means  of  Glycylt3rrosin,  Silk-peptone,  and 
Glycyltryptophane.  Optical  Method.  Inhibition  of  Proteolytic 
Processes  by  the  Products  of  Protein  Cleavage.  Classification  of 
Proteolytic  Ferments.    Peptolytic  Power  of  Blood  Serum. 


x  CONTENTS 

V.  Urea.    Hippüric  Acid     Excretion  of  Aminoacids 97 

Urea.  Theories  of  the  Formation  of  Urea  in  the  Living  Body. 
Uraminoacids.  Mechanism  of  Vital  Oxidation  of  Nitrogenous 
Substances.  Ammonium  Carbamate.  Place  of  Urea  Formation. 
Exclusion  of  the  Liver.  Alkalosis  and  Acidosis.  Arginase.  Post- 
coenal  Urea  Excretion.  Quantitative  Estimation  of  Urea.  Hip- 
puric Acid.  Source  of  Benzoic  Acid.  Hippuric  Acid  Elimination 
in  Carnivora  and  in  Man.  Hippuric  Acid  Formation  in  Herbivora. 
Behavior  of  Benzoylated  Aminoacids.  Synthetic  Source  of  Gly- 
cocoll  from  Acetic  Acid  and  Ammonia.  Glycocoll  and  Ornithin  as 
Detoxifying  Agents.  Quantitative  Estimation  of  Hippuric  Acid. 
Elimination  of  Aminoacids.  Aminoacids  in  Normal  Urine.  Elimi- 
nation of  Aminoacids  in  Disease.  Cystinuria  and  Diaminuria. 
Quantitative  Determination  of  Aminoacids. 

VI.  Creatin  and  Creatinin.     Other  Urinary  Bases.     Oxyproteic 

Acids.    Urochrome 122 

Creatin  and  Creatinin.  Quantitative  Estimation.  Relation 
Between  Creatin  and  Creatinin.  Creatase  and  Creatinase.  Endo- 
genous and  Exogenous  Distribution  of  Creatin-Creatinin  Elimina- 
tion. Relation  of  Creatin-Creatinin  Excretion  to  Decomposition 
of  Tissue  Protein.  Muscle  as  Source  of  Creatin.  Creatin  Cleavage 
from  Other  Tissues.  Test  of  Hepatic  Function.  Relation  of  Crea- 
tin Metabolism  to  Processes  in  the  Female  Sexual  Organs.  Pos- 
sible Origin  of  Creatin  from  Arginin.  Other  Urinary  Bases. 
Methylguanidin,  Dimethylguanidin,  Vitiatin.  Novain.  Trime- 
thylamine.  Arnold's  Reaction.  Urinary  Rest-Nitrogen.  Oxy- 
proteic Acids.  Fractionation  of  Oxyproteic  Acids.  Chemical 
Position  of  Urochrome.  True  Urochrome  and  Dombrowski's 
Urochrome.  Quantitative  Estimation  of  Oxyproteic  Acids. 
Elimination  of  Oxyproteic  Acids  in  Normal  and  Pathological 
Conditions.    Other  High-Molecular  Residual  Substances. 

VII.  Physiology  of  Purin  Metabolism 148 

Exogenous  and  Endogenous  Uric  Acid  Formation.  Conversion  of 
Adenin  and  Guanin  into  Uric  Acid.  Guanin  Gout  in  the  Hog. 
Nucleases  and  Deamidases.  Nuclear  Disintegration  and  Urinary 
Purins.  Relation  of  Purin  Metabolism  to  Muscular  Activity. 
Synthetic  Formation  of  Uric  Acid  in  Birds  and  Reptiles.  Synthetic 
Purin  Formation  in  Mammals.  Allantoin  as  an  End-product  of 
Mammalian  Purin  Metabolism.  Fate  of  Intermediary  Uric  Acid 
in  Man.  Absence  of  Uricase  in  Human  Tissues.  Fate  of  Experi- 
mentally Introduced  Purins  in  Human  Metabolism.  Decomposi- 
tion of  Purins  in  the  Intestine.  Reconstruction  of  Uric  Acid. 
Methylated  Purin  Derivatives.  Quantitative  Estimation  of  Uric 
Acid.    Wiechowski's  Method  of  Estimating  Allantoin. 

VIII.  Pathology  of  Purin  Metabolism 170 

Increase  of  Uric  Acid  in  the  Blood  of  the  Gouty.  Question  of 
Increase  in  the  Formation  of  Uric  Acid.  Question  of  Reduction 
of  Uric  Acid  Decomposition  in  Gout.  Curve  of  Uric  Acid  Excre- 
tion in  the  Acute  Gouty  Exacerbations.  Delayed  Nuclein  Ex- 
change in  the  Gouty.  Gout  and  Nephritis.  Uric  Acid  Retention. 
Affinity  of  Tissues  for  Uric  Acid.  Alkali  Compounds  of  Uric  Acid. 
Part  Taken  by  Changes  in  Alkalescence.  Lactam  and  Lactim 
Forms  of  Urates.  Nucleinic  Acid  Combination  With  Uric  Acid. 
Complex  Conditions  of  Solubility  of  Uric  Acid  in  Relation  to 
Uric  Acid  Diathesis.  Localization  of  Uric  Acid  Depositions. 
Alkalinity  of  Tissues  in  Relation  to  Uric  Acid  Deposit.  Attempts 
to  Produce  Gout  Experimentally.  Alcoholism.  Chronic  Plumb- 
ism.  Influence  of  Excessive  Meat  Diet.  Protracted  Feeding  of 
Nucleinic  Acid  to  Dogs.  Radium  Therapy  in  Gout.  Medicinal 
Treatment  of  Gout.    The  Diet  in  Gout. 


CONTENTS  xi 

IX.  Digestion  of  Carbohydrates.  Blood  Sugar.  Diastasic  Ferments  194 
Carbohydrate  Digestion.  Ptyalin.  Carbohydrate  Digestion  in 
the  Stomach.  Carbohydrate  Digestion  in  the  Intestine.  Role 
of  Pancreas  in  Production  of  Carbohydrate-splitting  Ferments. 
Fate  of  Disacch arides.  Dilution  of  Sugar  Solution  in  the  Intes- 
tine. Disappearance  of  Coarse  Vegetable  Fibres  from  the  Diges- 
tive Tract.  Determination  of  Cellulose.  Cytases.  Part  Taken 
in  Digestion  by  Enzymes  Contained  in  the  Food.  Importance 
of  Symbiotic  Microorganisms.  Marsh-Gas  Fermentation.  Food 
Value  of  Cellulose.  Importance  of  Infusoria  in  Cellulose  Digestion. 
Blood  Sugar.  Technic  of  Estimating  the  Sugar  in  the  Blood.  Ex- 
istence of  Free  Sugar  in  the  Blood.  Sucre  Immediat  and  Sucre 
Virtuel.  Does  the  Blood  Contain  Other  Carbohydrates  in  Addi- 
tion to  Glucose?  Sugar  Content  in  the  Red  Blood  Cells.  Sugar 
in  the  Aqueous  Humor.  Carbohydrate-splitting  Ferments. 
Quantitative  Determination  of  Diastase.  Wiechowski's  Tissue- 
Powder  Method.  Hepatic  Diastase.  Muscle  Diastase.  Diastases 
in  Embryos.  Origin  of  Diastase.  Role  of  Pancreas  in  the  Produc- 
tion of  Blood  Diastase.  Maltases,  Invertases  and  Glucases  in  the 
Blood-serum.    Action  of  Diastase  on  Various  Forms  of  Starch. 

X.  Glycogen.    Formation  of  Sugar  from  Protein  and  Fat 221 

Glycogen.  Quantitative  Determination  of  Glycogen.  Chemistry 
of  Glycogen.  Relation  Between  Consumption  of  Sugar  by  the 
Muscles  and  the  Disappearance  of  Glycogen  in  the  Liver.  Pro- 
duction of  Glycogen  Impoverishment  in  the  Body.  Glycogen 
Formation  in  the  Perfused  Liver.  Glycogen  Formation  from 
Glucose,  Fructose,  and  Galactose.  Behavior  of  Disaccharides  and 
Polysaccharides.  Other  Substances  of  the  Sugar  Series.  Glycogen 
Formation  from  Formaldehyde.  Limit  of  Saturation  and  Utili- 
zation. Formation  of  Sugar  from  Protein.  Carbohydrate  Group 
in  the  Protein  Molecule.  Elimination  of  Sugar  and  Protein  De- 
composition. Respiration  Experiments.  New  Formation  of  Car- 
bohydrate in  Glycogen-Free  Tissues.  Formation  of  Sugar  from 
Various  Proteins.  Origin  of  Sugar  from  Animoacids.  Formation 
of  Sugar  from  Fat.  Sugar  Formation  from  Glycerine.  Seegen's 
Experiments.  Respiratory  Quotient  in  Diabetes.  Sugar-Nitrogen 
Quotient.  Fat  Impoverishment  in  Phloridzin  Animals.  Influence 
of  the  Introduction  of  Higher  Fatty  Acids  upon  Sugar  Elimina- 
tion, 

XI.  Pancreatic  Diabetes.    Human  Diabetes 247 

Pancreatic  Diabetes.  Discovery  of  Pancreatic  Diabetes.  Inter- 
rupted Extirpation  of  the  Pancreas.  Function  of  Islands  of  Lan- 
gerhans, Duodenal  Diabetes.  Does  the  Internal  Secretion  of  the 
Pancreas  Pass  with  the  Lymph  through  the  Thoracic  Duct  into 
the  Blood?  Blood  Transfusion  and  Parabiosis.  Glycogen  Forma- 
tion, Diastasic  Power  and  Formation  of  Sugar  from  Carbohydrate- 
free  Material  in  the  Liver  in  Pancreatic  Diabetes.  Glycolysis. 
Oxidation  Processes  in  the  Diabetic  Economy.  Metabolism  in 
Pancreatic  Diabetes.  Partial  Extirpation  of  Pancreas.  Antipan- 
creatin  Serum.  Isolation  of  the  "  Pancreatic  Hormone."  Human 
Diabetes.  Degeneration  of  the  Pancreas  in  Human  Diabetes. 
Glycogen  Content  of  the  Liver.  Hyperglycemia.  Methylene- 
Blue  Reaction  of  the  Blood.  Urinary  Dextrine.  Protein  Destruc- 
tion. Diabetic  Lipsemia.  Respiration  Experiments  in  Diabetes. 
Substitutes  for  Bread  for  Diabetics.  Oat  Treatments.  Influence 
of  Mineral  Waters.    Medicinal  Treatment  of  Diabetes. 

XII.  Phloridzin    Diabetes.      L^evulosuria.      Lactosuria.      Pento- 
suria.   Experimental  Glycosurias  of  Different  Kinds.  . . .  275 
Phloridzin  Diabetes.     Lack  of  Hyperglycaemia.     Role  of  the 
Kidney.    Formation  of  Sugar  in  the  Kidney.    Fate  of  Phloridzi  a 


xii  CONTENTS 

in  the  Body.  Laevulosuria.  Detection  of  Laevulose.  Trans- 
formation of  Glucose  into  Laevulose.  True  Laevulosuria.  Ali- 
mentary Laevulosuria.  Lactosuria.  Lactosuria  of  Puerperal 
Women.  Lactosuria  in  Infants.  Alimentary  Galactosuria  in 
Disturbances  of  Hepatic  Functions.  Pentosuria.  X-xylose. 
Alimentary  Pentosuria.  Pentosuria  in  Diabetes.  Chronic  Pen- 
tosuria. Detection  of  Pentoses.  Cammidge  Reaction.  Experi- 
mental Glycosurias  of  Various  Kinds.  Renal  Glycosurias. 
Sugar  Puncture.  Toxic  Glycosurias.  Salt  Glycosuria.  Gly- 
cosuria from  Chill. 

XIII.  Relation  of  Glands  with  Internal  Secretion  to  Carbohy- 

drate Metabolism.    Glycuronic  Acid 300 

Relations  of  the  Adrenals  to  Carbohydrate  Metabolism.  Nature 
of  Adrenal  Diabetes.  Dependence  of  Adrenin  Glycosuria  upon 
the  Renal  Function.  Hypothesis  of  the  Regulating  Influence 
of  Adrenin  upon  Normal  Carbohydrate  Metabolism.  Does 
the  Sugar  Puncture  Act  through  the  Adrenals  to  Cause  Glyco- 
suria? Failure  of  Effect  of  Glycosuric  Puncture  After  Exclusion 
of  the  Adrenals.  Chromium  Affinity  of  the  Adrenals.  Question 
of  Increase  of  Adrenin  after  Sugar  Puncture.  Do  the  Adrenals 
Have  a  Regulating  Influence  upon  the  Normal  Carbohydrate 
Metabolism?  Relations  of  the  Thyroid  Gland  to  Carbohydrate 
Metabolism.  Removal  of  the  Thyroid  and  of  the  Parathyroids. 
Hyperthyroidism.  Interaction  of  the  Internal  Secretory  Glands. 
Relation  of  Hypophysis  to  Carbohydrate  Metabolism.  Gly- 
curonic Acid.  Constitution.  Conjugation  Conditions.  Origin 
of  Glycuronic  Acid  from  Oxidation  of  Sugar.  Oxaluria.  Con- 
version of  Glycuronic  Acid  into  X-xylose.  Occurrence  of  Gly- 
cyronic  Acid  in  the  Body.  Importance  of  Glycuronic  Acid  in 
Diagnosis  of  Intestinal  Disturbances  and  Diseases  of  the  Liver. 
Detection  and  Estimation  of  Glycuronic  Acid. 

XIV.  Sugar  Destruction  in  the  Economy 327 

Glycolysis.  Distribution  of  Zymases  in  the  Vegetable  Kingdom. 
Supposed  Occurrence  of  Zymases  in  Animal  Tissues.  Cohn- 
heim's  Pancreas-Muscle  Experiments.  Objections  of  Claus  and 
Embden.  Possible  Existence  of  Glycolytic  Tissue  Ferments. 
Experiments  upon  Surviving  Tissues.  Glycolysis  in  Blood. 
Importance  of  Leucocytes  in  Blood-Glycolysis.  Sugar  Catabol- 
ism  from  the  Influence  of  Alkali.  Importance  of  Catalyzers  in 
the  Catalysis  of  Sugar.  Electrolytic  Cleavage  of  Sugar.  Mech- 
anism of  Alcoholic  Fermentation  of  Sugar.  Butyric  Acid  Fer- 
mentation.   Citric  Acid  Fermentation. 

XV.  Digestion  and  Resorption  of  Fats 350 

The  Lipase  of  the  Stomach.  Problems  of  Fat  Resorption.  Fat 
Cleavage  and  Solution  of  Cleavage  Products.  Fat  Synthesis 
in  the  Intestinal  Wall.  Behavior  of  Non-Saponifiable  Emul- 
sions. Histological  Observations  Bearing  upon  Fat  Resorption. 
Resorption  of  Soaps.  Method  of  Study  with  Isolated  Intestinal 
Loops.  Influence  of  Pancreatic  Juice  and  Bile  upon  Fat  Diges- 
tion. Influence  of  Extirpation  of  Pancreas  upon  Fat  Resorption. 
Activation  of  Pancreatic  Steapsin  by  Salts  of  the  Biliary  Acids. 
Question  of  Complex  Nature  of  Pancreatic  Steapsin.  Synthetic 
Production  of  Fat  by  Reverse  Ferment  Action  of  Lipase.  Fat 
Cleavage  in  the  Intestine  in  the  Absence  of  Pancreatic  Secretion. 
Solvent  Power  of  the  Bile.  Lipaemia.  Resorption  Path  of  the 
Fat.  Haemoconiosis.  Masking  of  the  Fat  in  the  Blood.  Rela- 
tion of  the  Masking  of  Fat  to  Fatty  Degeneration.  Pathologi- 
cal Lipsemias.  Lipaemia  from  Mobilization  of  Fat  Deposits. 
Diabetic  Lipaemia.  Lipaemia  from  Narcosis.  Passage  of  the 
Fat  out  of  the  Blood  Stream.  Fetal  Lipaemia.  Diet  Lipaemia. 
Pavy's  Theory. 


CONTENTS  xiii 

XVI.  Fat  Metabolism.    Obesity 378 

Dependence  of  Protein  Destruction  upon  the  Fat  Supply.  Im- 
portance of  Lipoids  in  Nutrition.  Parenteral  Fat  Absorption. 
Fat  Storage  in  the  Body.  Deposit  of  Foreign  Fat.  Transfor- 
mation of  Fat  in  the  Body.  Depot  Fat  and  Cell  Fat.  Oxidative 
Function  of  the  Liver  in  Catabolism  of  Higher  Fatty  Acids. 
Formation  of  Fat  from  Sugar.  Transformation  of  Fat  into 
Carbohydrate  in  the  Vegetable  Economy.  Characteristics  of 
Fat  which  is  Formed  de  novo  from  Carbohydrates.  Place  of 
Origin  of  Fat  from  Carbohydrates.  Chemistry  of  Fat  Formation 
from  Sugar.  Experiments  upon  the  Disintegration  of  Fat  by 
Plants.  Catabolism  of  Fatty  Acids  in  the  Animal  Body.  Nature 
of  Obesity.  Corpulence  and  Over-feeding.  Antifat  Treatments. 
Fattening. 

XVII.  Fat-Splitting  Tissue  Ferments.     Fat  Formation  From  Pro- 

tein.   Fatty  Infiltration  and  Fatty  Degeneration.    Origin 

of  Milk-Fat .............  401 

Fat-Splitting  Tissue  Ferments.  Fat  Cleavage  in  the  Blood. 
Lipase  of  the  leucocytes.  Cleavage  of  Esters  in  the  Tissues. 
Fat-Splitting  Tissue  Ferments.  Formation  of  Fat  from  Protein. 
Fatty  Degeneration  and  Fatty  Infiltration.  Fat  Phanerosis  in 
Autolysis.  Nature  of  Fat  Phanerosis.  Formation  of  Higher 
Fatty  Acids  by  Microorganisms.  Hoffmann's  Experiment  with 
Fly-Maggots.  Adipocere.  Formation  of  Fat  in  Ripening  of 
Cheese.  Accumulation  ot  Fat  in  the  Liver  in  Phosphorus 
Poisoning.  Fatty  Degeneration  of  the  Liver.  Fatty  Infiltration 
in  Other  Pathological  Conditions.  Rosenfeld's  Theory.  Asso- 
ciation of  Fat  Phanerosis  in  the  Phenomena  of  Fatty  Degenera- 
tion. Fatty  Change  of  the  Kidney.  Cholesterol-Ester  Steatosis. 
Origin  of  Milk  Fat.  Passage  of  the  Fat  of  the  Food  into  the 
Milk.  Origin  of  Milk  Fat  from  the  Carbohydrates  of  Food. 
Lower  Fatty  Acids  in  Milk.  Sebaceous  Glands  and  Coccygeal 
Gland.    Haptogenic  Membranes. 

XVIII.  Acetone  Bodies •  •  431 

Acetone  Bodies.  Relation  of  Acetone  Body  Formation  to  the 
Corporeal  Fat  and  to  that  of  the  Food.  Origin  of  Acetone 
Bodies  from  the  Lower  Fatty  Acids  with  Even  Carbon  Atom 
Chain.  Possibility  of  Disintegration  of  the  Longer  Fatty  Acid 
Chains  into  Short  Parts.  Is  /3-oxybutyric  Acid  a  Product  of 
Normal  Metabolism?  Derivation  of  Acetone  Bodies  from  Com- 
pounds with  Branched  and  Cyclical  Chains.  Carbohydrate 
Deficiency  and  Acidosis.  Diabetic  Coma.  Alkaline  Treatment 
of  Coma.  Antiketogenic  Substances.  Ammonia  Elimination 
and  Acidosis.  Interrelations  of  Acetone  Bodies.  Determina- 
tion of  Acetone  and  Diacetic  Acid.  Quantitative  Determina- 
tion of  Oxybutyric  Acid. 

XIX.  Lactic  Acid.  Fate  of  Body-Foreign  Substances  in  the  Economy  452 
Lactic  Acid.  Quantitative  Estimation  of  Lactic  Acid  by  the 
Method  of  Fürth  and  Charnass.  Determination  of  Lactic  Acid 
and  /3-oxybutyric  Acids  Together.  Ryffel's  Method  of  Lactic 
Acid  Determination.  Postmortem  Formation  of  Lactic  Acid. 
Origin  of  Lactic  Acid  from  Sugar.  Embden's  Schema  of  Sugar 
Catabolism  in  the  Living  Body.  Glycerol-Aldehyde  as  an  Inter- 
mediate Product  between  Sugar  and  Lactic  Acid.  Racemic 
Acid  as  an  Intermediate  Product.  Appearance  of  Lactic  Acid 
in  the  Urine.  Fate  of  Body-Foreign  Materials  in  the  Economy. 
Decomposition  of  Fatty  Acids  and  Aliphatic  Sidechains.  Ca- 
tabolism of  a-aminoacids.  Oxidation  of  Cyclic  Nuclei.  Reduc- 
tion Processes  in  the  Economy.     Deaminization.     Synthetic 


xiv  CONTENTS 

Formation  of  Aminoacids  in  the  Animal  Body.  Acetylizing 
Processes  in  the  Animal  Body.  Alkylation.  Detoxification  by 
Sulphuric  Acid  and  Sulphur-containing  Rests.  Conjugation 
with  Glycocoll  and  Ornithin.  Uraminoacids.  Behavior  of 
Stereoisomeric  Substances  in  the  Body. 

XX.  Nutritional  Requirements.  Fasting.  Parenteral  Nutrition  482 
Nutritional  Requirements.  Amount  of  Food.  Metabolic  Mini- 
mum. Protein  Minimum.  Relation  Between  Protein  Require- 
ment and  Total  Energy  Requirement.  Vegetarianism.  Mechan- 
ical Preparation  of  Vegetable  P'ood.  Nitrogen  Balance.  Tissue 
Protein  and  Circulating  Protein.  Specific-Dynamic  Action  of 
Protein.  Physiological  Value  of  Various  Proteins.  Heterospe- 
cific  and  Homospecific  Proteins.  Food  Composed  of  Simple  Sub- 
stances. Velocity  of  Protein  Catabolism.  Metabolism  in  Fast- 
ing. How  Long  May  Hunger  and  Thirst  be  Endured?  Loss  of 
Weight  of  the  Organs.  Total  Metabolism  in  Inanition.  Protein 
Economics  in  Inanition.  Carbohydrate  Metabolism.  Urine  in 
Inanition.  Respiratory  Quotient.  Hibernation.  Rhine  Sal- 
mon; Batrachian  Larva?.  Sensation  of  Hunger.  Parenteral 
Introduction  of  Protein.  Parenteral  Feeding  with  Sugar. 
Parenteral  Feeding  with  Fat. 

XXI.  Technic  of  Study  of  Gas  Exchange.  Maintenance  Metabol- 
ism and  Growth.  Energy  Exchange  from  Ingestion  of  Food  514 
Methods  of  Gas  Exchange  Studies.  Pettenkofer  Type  of  Res- 
piration Apparatus.  Regnault  and  Reiset  Type  of  Respiration 
Apparatus.  Respiration  Calorimeter  of  Atwater  and  Benedict. 
Method  of  Zuntz  and  Geppert.  Other  Methods.  Question  of 
Part  Taken  by  Elemental  Nitrogen  and  Hydrogen  in  Metabol- 
ism. Maintenance  Exchange  and  Growth.  Significance  of  Sur- 
face Development  and  Volume  of  Body  Protein.  Energy  Cal- 
culation in  Infancy.  Laws  of  Growth.  Energy  Exchange  after 
Ingestion  of  Food.  Physiological  Utilization  Value.  Range  of 
Metabolic  Increase.  Work  of  Digestion.  Specific-Dynamic 
Effect  of  Proteins. 

XXII.  Oxidation  Ferments 534 

Theory  of  Action  of  Oxidases.  Peroxidases  and  Oxygenases. 
Sources  of  Error  in  Study  of  Peroxidases.  Iodine  Reaction.  Oxi- 
dation of  Formic  Acid.  Purpurogallin  Method.  Phenolphtha- 
lin  Method.  Leucomalachite-green  Methods.  Measurement 
of  Oxygen  Consumption.  Limit  of  Availability  of  Above  Meth- 
ods. Peroxidase-like  Action  of  Haemoglobin.  Chemico-Legal 
Detection  of  Blood  by  Means  of  Peroxidase  Reactions.  Res- 
piratory Coloring  Substances.  Artificial  Peroxidases.  Doubt 
as  to  the  Ferment  Character  of  Peroxidases.  Indophenoloxi- 
dases.     Purin  Oxidases.     Aldehydases.     Summary. 

XXIII.  Catalases.   Tissue  Respiration 556 

Catalases.  Definition  of  Catalases.  Demonstration.  Deter- 
mination of  Activity  of  Catalase  Preparations.  Physiological 
Significance  of  Catalases.  Tissue  Respiration.  Cardinal  and 
Accessory  Respiration.  Reducing  Tissue  Components.  Oxygen 
Consumption  in  the  Blood.  Living  and  Dead  Protein.  Meth- 
ods of  Study  of  the  Respiration  of  Isolated  Organs.  Barcroft 
and  Haldane  Blood  Gas  Analysis.  Cohnheim's  Respiration 
Apparatus  for  Isolated  Organs.  Thunberg's  Microrespirometer. 
Gas  Interchange  of  Muscle.  Oxygen  Requirement  of  Nervous 
Tissue.  Gas  Interchange  of  Salivary  Glands.  Gas  Exchange 
in  the  Liver  and  Kidney.  Gas  Exchange  in  the  Intestine.  An- 
oxybiotic  Processes. 


CONTENTS  xv 

XXIV.  The  Coloring  Matter  of  the  Blood.  Blood  Gases.  Gas  Inter- 

change in  the  Lungs.    Physiology  op  Alpinism 579 

Haemoglobin.  Production  of  Haemoglobin  Crystals.  Variability 
of  Haemoglobin.  Hoemochrome  and  Crystallized  Blood  Coloring 
Matter.  Individuality  of  Haemoglobin.  Importance  of  Iron  in 
the  Blood  Coloring  Matter.  Methaemoglobin.  Blood  Gases. 
Technic  of  Blood-Gas  Analysis.  Objective  Haemoglobinometry 
and  Spectrophotometry.  Coefficients  of  Absorption,  Invasion 
and  Evasion.  Tension  Curves.  Influence  of  Carbonic  Acid 
Pressure.  Influence  of  Temperature.  Influence  of  the  Salts  in 
the  Medium  and  Other  Factors.  Physical-Chemical  Concep- 
tion of  Oxygen  Fixation  by  Haemoglobin.  Carbonic  Acid  Com- 
bination in  Blood.  Process  of  Exchange  Between  the  Blood 
Corpuscles  and  Serum.  Gas  Exchange  in  the  Lung  Mechanism 
of  Gas  Exchange.  Secretion  of  Oxygen  in  the  Swim-Bladder  of 
Fish.  Partial  Pulmonary  Exclusion.  Cutaneous  Respiration. 
Intestinal  Respiration.  Physiology  of  Alpinis-m.  Sources  of 
Observation  Material.  Influence  of  Climatic  Factors.  Increase 
of  Blood  Corpuscles.  Changes  in  Cardiac  Activity.  Changes 
of  Respiration.  Acapnia.  Loss  in  Alkalescence  of  the  Blood. 
Increase  of  Energy  Exchange.     Nitrogen  Retention. 

XXV.  Fever 610 

Total  Exchange.  Influence  of  Increased  Muscular  Activity. 
Increase  of  Reaction  Velocity  of  Metabolic  Processes  with  the 
Temperature.  Frugality  of  Body  in  Chronic  Febrile  Conditions. 
Respiratory  Quotient.  Reduction  Power  of  Tissues.  Decreased 
Heat  Elimination.  Protein  Destruction.  Inhibition  of  Febrile 
Protein  Destruction  by  Increasing  Carbohydrate  Food .  Elimina- 
tion of  Nitrogenous  Metabolic  End-Products.  Acidosis  and  Fat 
Destruction.  Relation  of  Carbohydrate  Metabolism  to  Fever. 
Changes  in  the  Constitution  of  Blood  Plasma.  Water  Economy 
in  I'ever.  Swelling  of  Cellular  Protoplasm.  Chlorine  Retention. 
Chemical  and  Physical  Heat  Regulation.  Importance  of  Nerv- 
ous System  in  Regulation  of  Temperature.  Fixation  of  Heat 
Regulation  at  a  Higher  Level.  Increased  Excitability  of  Heat 
Regulating  Centres  in  Fever  and  its  Reduction  by  Antipyretics. 
Pyrogenic  Properties  of  Proteins  and  Protein  Derivatives. 
Fever  Following  the  Introduction  of  Corpuscular  Elements  into 
the  Circulation.  Hyperthermias  Produced  by  Chemically 
Definite  Substances.  Salt-  and  Sugar-Fever.  Significance 
of  Fever.  Epilogue. 


THE    PHYSIOLOGICAL  AND 

PATHOLOGICAL   CHEMISTRY 

OF   METABOLISM 

CHAPTER  I 

INTRODUCTION  TO  THE  STUDY  OF  METABOLISM. 
PROTEIN  DIGESTION  IN  THE  STOMACH 

INTRODUCTORY 

Every  one  knows  full  well  with  what  feelings  of  joy  and 
satisfaction  the  mountain  climber  after  long  and  tiresome 
trudging  at  last  reaches  some  hoped-for  height  and  views 
the  silent  space  around  and  about  him.  If  fortune  smile 
and  the  blue  dome  arch  out  before  him  without  a  cloud  to 
its  farthest  reaches,  how  easy  it  is  for  the  wanderer  to  lose 
himself  in  contemplation  of  the  unending,  shining  distances, 
and  to  allow  to  dawn  within  him  a  shadowy  presentment  of 
the  eternal  and  infinite.  But  days  of  such  good  luck  are  rare ; 
much  more  often  the  traveller  on  the  heights  must  be  satisfied 
if  spiteful  mists  do  not  completely  cheat  him  of  the  reward 
of  his  labor,  and  if  some  little  part  of  the  majesty  he  had 
hoped  to  look  upon  remain  unfilched  from  view.  It  may  well 
be  that  only  one  small  part  in  all  that  mountain  world  stands 
forth  in  sharply  outlined  configuration  to  satisfy  his  gaze. 
All  other  regions  seem  covered  by  a  vast  cloak  of  vapor,  with 
only  the  uncertain  shadows  of  grosser  outlines  shown.  In 
the  far  distances  lie  thick  banks  of  clouds  and  rolling,  steam- 
ing shapes  of  mist,  sweeping  out  from  the  clefts,  clinging  in 
the  valleys,  and  refusing  to  permit  even  a  guess  of  what  lies 
buried  behind  them. 

So,  too,  with  us,  after  long  and  tiresome  wandering,  this 
mountain  pass  is  attained;1  from  which  we  may  hope  to 
advance  some  little  way,  perchance,  into  the  broad,  mys- 
terious domain  of  the  physiology  of  metabolism.    In  allur- 

1  Referring  to  the  series  of  lectures  preceding  the  present  text,  in  the 
volume  entitled  "  Chemistry  of  the  Tissues,"  in  the  original  German  edition. 

1 


2         INTRODUCTION  TO  STUDY  OF  METABOLISM 

ing  change  are  unfolded  splendid  open  stretches  in  full  bright 
light,  and  dark  cloaks  of  vapor  with  only  here  and  there  a 
ray  breaking  through ;  thick,  still  banks  of  clouds,  and  rolling 
veils  of  mist  through  which  the  picture,  before  clear  and 
transparent,  becomes  in  the  next  moment  dark  and  uncertain. 

We  view  with  wonder  and  admiration  the  vast  amount 
of  labor  which  has  been  devoted  to  the  study  of  metabolism 
since  the  days  when  Lavoisier  first  recognized  the  vital 
combustion  processes  and  since,  long  after,  Robert  Meyer 
and  Herman  v.  Helmholtz  inflamed  with  their  genius  a  torch 
destined  to  cast  its  beams  of  light  into  the  darkness  of  all 
fact  and  error  in  the  domain  of  vital  phenomena.  Under 
the  dominance  of  the  law  of  conservation  of  energy  the  newer 
physiology  of  nutrition,  founded  by  Liebig,  Pettenkof er,  Voit 
and  Pflüger,  is  seen  to  arise;  modern  chemistry  at  the  task 
of  uncovering  the  secrets  of  the  intermediate  metabolism; 
and  pathologists  in  earnest  endeavor  to  open  to  physiology 
the  experiments  on  man  which  nature  provides.  But,  on 
the  other  hand,  how  slow  the  steps  of  progress  to  one  who 
never  turns  to  observe  the  long  path  already  traversed  but 
keeps  ever  before  him  the  goal  constantly  receding  into  the 
distance  before  his  advance. 

In  undertaking  to  present  a  clear  outline  of  the  problems 
which  mainly  occupy  the  attention  of  metabolic  physiologists 
to-day  it  seems  best  to  the  author,  in  conformity  with  the  plan 
followed  in  the  preceding  volume  upon  the  Chemistry  of  the 
Tissues,  which  started  with  a  discussion  of  the  protein  prob- 
lem, to  begin  this  study  of  metabolism  also  with  the  proteins. 
The  proteins  and  their  catabolic  products  will  be  first  con- 
sidered, tracing  them  from  their  ingestion  into  the  stomach 
as  food,  in  their  course  through  the  body  until  their  deriva- 
tives disappear  in  the  unknown  processes  of  intermediate 
metabolism.  In  turn  the  carbohydrates  and  fats  will  be 
taken  up  in  the  same  way ;  in  preparation  for  the  considera- 
tion, finally,  of  the  vital  combustion  processes,  the  most  im- 
portant phases  of  metabolic  physiology.    It  is  no  short  and 


"MOCK  MEAL"  3 

easy  path  along  which  the  student  is  invited  to  trudge  with 
the  author.  Yet  it  is  scarcely  in  harmony  with  the  duty 
of  a  guide  that  at  the  very  beginning  of  an  ascent  he  should 
paint  fearful  pictures  of  its  difficulties.  It  is  very  much 
better  to  take  up  the  way  confidently  and  without  misgivings, 
and  to  postpone  to  convenience  all  matters  of  reflection. 

Without  further  introduction,  therefore,  the  subject- 
matter  of  the  lecture  may  be  taken  up : 

PROTEIN  DIGESTION  IN  THE  STOMACH 

In  all  the  mammalia,  it  need  scarcely  be  said,  the  food 
after  mechanical  preparation  by  mastication  passes  to  a 
reservoir,  the  stomach,  where  its  proteid  constituents  under- 
go at  once  the  first  phase  of  digestion  under  the  influence  of 
the  peptic  ferment  of  the  stomach. 

"Mock  Meal"  and  Pawlow's  Ventriculus. — Investiga- 
tions bearing  upon  the  secretion  of  the  gastric  digestive 
juice  in  subjects  having  operative  or  traumatic  gastric  fis- 
tulas date  back  to  the  first  half  of  the  past  century.  A  sys- 
tematic experimental  study  of  the  problem  of  the  secretory 
function  of  the  gastric  mucous  membrane  was  first  made 
possible  when  Pawlow la  perfected  a  satisfactory  technic 
of  artificial  production  of  gastric  fistula. 

In  his  method  the  oesophagus  is  diverted  in  the  neck, 
in  a  dog  in  which  a  gastric  fistula  has  been  produced,  to  the 
surface  and  the  orifice  is  stitched  into  the  skin  wound;  so 
that  by  the  passage  of  a  "mock  meal"  considerable  quanti- 
ties of  pure  gastric  juice  without  admixture  of  food  sub- 
stances may  be  obtained  from  the  fistula,  as  all  the  food 
given  the  hungry  animal  passes  out  of  the  upper  part  of  the 
gullet  to  the  exterior,  while  at  the  same  time  the  nervous 
secretory  stimulus  ("psychic  secretion")  excited  by  the  act 
of  chewing  operates  without  complicating  factors. 

Pawlow  contributed  another  important  step  by  his  modifi- 
cation of  Haidenhain's  method  of  making  a  ventriculus  or 

aa  J.  P.  Pawlow,  Arbeit  der  Verdauungsdrüsen,  Wiesbaden,  1898;  and 
Nagel's  Handb.  d.  Physiol.,  2,  699-762,  1907. 


4  GASTRIC  DIGESTION  OF  PROTEINS 

*  'little  stomach. ' '  By  simply  cutting  out  of  the  gastric  wall 
a  section,  closing  the  wound  in  the  stomach  and  stitching  the 
blind  sac  constructed  from  the  exsected  patch  into  the  ab- 
dominal wound,  a  "ventriculus"  is  formed,  which  during 
digestion  secretes  coincidently  with  the  stomach  itself.  In 
the  older  method,  however,  the  secretory  nerves  are  divided 
and  the  secretory  conditions  are  therefore  by  no  means 
normal.  Pawlow  corrected  this  fault  in  his  method  of  oper- 
ating, by  freeing  completely  only  the  mucous  membrane  of 
the  patch  and  sparing  a  pedicle  of  the  serous  and  muscular 
coats  in  attachment  with  the  stomach  proper,  so  that  the 
vagus  fibres  going  to  the  mucosa  may  pass  from  the  wall  of 
the  large  stomach  to  that  of  the  small  stomach  by  route  of 
the  pedicle.  He  has  been  able  to  show  that  the  vagus  nerve 
actually  conducts  secretory  impulses  to  the  stomach  by  the 
following  methods.  If  both  vagi  are  excluded,  either  by 
section  or  by  atropine,  the  usual  result  of  the  "mock  meal" 
fails  to  appear;  by  stimulation  of  a  peripheral  vagus  seg- 
ment gastric  secretion  can  be  induced,  provided  stimulation 
is  not  practiced  immediately  after  the  section  but  preferably 
after  sufficient  time  has  elapsed  for  the  degeneration  of  the 
vagus  cardiac  fibres. 

Nervous  Mechanism  of  Secretion. — Efficient  secretory 
stimulus,  passing  from  the  cortex  of  the  brain  by  way 
of  the  vagus  nerves  to  the  stomach,  producing  in  case  of 
the  "mock  meal"  experiment  a  full  complement  of  active 
gastric  juice,  fails  after  section  of  the  vagi;  but  after  a 
time  a  certain  amount  of  gastric  adaptation  takes  place 
whereby  a  continuous  secretion  is  maintained  sufficient 
for  the  digestive  requirements.2  Bickel  has  observed  con- 
tinuous secretion  of  normal  gastric  juice  in  the  nerveless 
stomach  in  a  dog  in  which  he  cut  all  the  extra  gastric  nerves 
of  a  gastric    diverticulum.3 

3  P.  Katschowsky    (Pawlow's  Laboratory),   Pfliiger's  Arch.,   84,   6,   1901. 

3  A.  Bickel,  Deutsche  med.  Wochenschr.,  1909,  704.  Literature  on  the 
neuro-secretory  mechanism  of  gastric  secretion :  A.  Bickel,  Handb.  d.  Biochemie, 
3',  58-63,  1910. 


ACTION  OF  PSYCHIC  INFLUENCES  5 

By  a  long  series  of  painstaking  and  carefully  conducted 
investigations,  the  majority  of  which  were  done  in  the  Insti- 
tute of  St.  Petersburg  and  in  the  laboratory  of  A.  Bickel  in 
Berlin,  the  excito-secretoiy  influence  exerted  upon  the  gas- 
tric secretion  by  a  great  variety  of  physiological  and  patho- 
logical factors  has  been  determined,  including  foodstuffs, 
condiments,  mineral  waters,  medicinal  substances,  and  the 
like.4  These  studies  have  been  very  materially  supplemented 
by  observations  upon  human  beings  with  gastric  fistulas,5  in 
whom  occasionally  the  same  conditions  have  existed  as  obtain 
in  the  experimental  "mock  meal"  procedures.  For  ex- 
ample, in  the  case  of  a  girl  who  had  had  a  gastric  fistula 
produced  after  a  corrosive  lesion  of  the  oesophagus,  an 
cesophagotomy  was  later  performed,  and  by  means  of  a  rub- 
ber tube  direct  communication  established  between  the  end 
of  the  upper  oesophageal  segment  and  the  gastric  fistula. 
Well-masticated  morsels  were  transmitted  with  considerable 
force  by  the  muscles  of  the  gullet  along  this  artificial 
oesophagus  into  the  stomach ;  while  by  removal  of  the  com- 
municating tube  the  precise  arrangement  of  a  regular 
"mock-meal"  experiment  was  obtained. 

Action  of  Psychic  Influences. — In  endeavoring  to  come  to 
some  definite  understanding  from  the  various  studies  upon 
animals  and  human  beings  as  to  the  factors  by  which  the 
secretion  of  the  gastric  juice  is  most  actively  affected,  we  can- 
not fail  to  recognize  the  dominating  agency  of  psychic  influ- 
ence. We  know  to-day  that  under  appropriate  conditions  the 
mere  idea  of  a  toothsome  meal,  and  to  a  greater  degree  the 
actual  mastication  of  such  food,  not  only  ' '  make  the  mouth 
water"  but  also  make  the  juices  of  the  stomach  flow.  An  as- 
sociative gastric-juice  production  has  been  clearly  proved  to 

4 Literature:  0.  Cohnheim,  Nagel's  Handb.  d.  Physiol.,  2,  534-542,  1907. 
A.  Bickel,  Handb.  d.  Biochemie,  3',  66-70,  1910. 

*  Observations  of  F.  A.  Hornborg,  F.  Umber,  H.  Bogen,  A.  Bickel,  Sasaki, 
H.  Kaznelson,  Pflüger's  Archiv.,  118,  327,  1907;  R.  S.  Lavenson,  Arch.  Int.  Med., 
k,  271,  1909;  Cf.  O.  Cohnheim,  Die  Physiologie  d.  Verd.  u.  Ernährung,  p.  57, 
1908. 


6  GASTRIC  DIGESTION  OF  PROTEINS 

exist  in  the  case  of  a  child  with  gastric  fistula.  Each  time  the 
little  patient  received  food  a  certain  note  was  sounded  on  a 
child 's  trumpet ;  and  after  a  time,  during  which  this  practice 
was  continued,  the  sound  of  the  trumpet  alone,  without  the 
actual  food,  sufficed  to  cause  a  flow  of  gastric  secretion.6  That 
anger  and  agitation  disturb  the  appetite  is  a  comparatively 
common  experience  of  almost  every  one  of  us.  But  Bickel 
has  produced  experimental  evidence  in  the  same  line,  by 
showing  that  a  dog  whose  equanimity  was  banished  by  the 
irritating  sight  of  a  cat  not  only  manifested  loss  of  appetite 
from  anger,  but  in  addition  suffered  actual  cessation  of 
gastric  secretion  during  his  period  of  indignation.7  The 
normal  taste  perceptions  are,  however,  not  invariable  prece- 
dents of  actual  gastric  secretion;  as  Coronedi  observed  in 
the  course  of  a  "mock  meal"  experiment  the  production  of 
an  entirely  normal  gastric  juice  after  having  completely 
anaesthetized  the  tongue  of  the  experiment  animal  against 
sense-perception  by  painting  it  with  cocaine  solution.8 

Excito-Secretory  Stimuli. — Mechanical  irritants  have  lit- 
tle effect  in  inducing  secretion  of  the  gastric  juice.  However, 
although  Pawlow  has  denied  their  influence  completely, 
Arthur  Schiff  has  been  able  to  present  evidence  that  chronic 
irritation,  as  from  sand  particles  and  similar  substances  in 
fluid  suspension,  may  be  effective,  at  least  in  the  sense  of  in- 
creasing the  secretory  flow.9  In  the  same  connection  may 
be  mentioned  the  fact  that  in  dogs  with  the  pylorus  con- 
stricted by  a  silver  band  there  occurs  a  continuous  gastric 
secretion.10 

In  comparing  various  foodstuffs,  the  most  active  secre- 
tory flow  is  noted  after  feeding  meat.  It  has  been  shown, 
too,  that  meat-extractives  are  particularly  influential;   but 


eH.  Bogen  (Kinderklinik,  Heidelberg),  Pfltiger's  Arch.,  117,  150,  1907. 
7  A.  Bickel,  Deutsche  med.  Wochenschr.,  1905,  1829. 

*G.  Coronedi  and  F.  Delitala,  Arch,  di  Fisiol  (Festschr.  f.  Fano),  7,  17; 
Centralbl.  f.  d.  Ges.  Biol.,  10,  No.  1915,  1910. 

»A.  Schiff  (Inst.  R.  Paltauf),  Zeitschr.  f.  klin.  Med.,  61,  220,  1907. 

10  N.  B.  Foster  and  A.  V.  S.  Lambert,  Proc.  Soc.  Exper.  Biol.,  5,  109,  1908. 


GASTRIC  SECRETIN  7 

it  is  not  known  to  what  particular  component  of  the  extract 
this  special  secretion-stimulation  is  due.  The  flesh  of  fish 
seems  to  be  more  effective  than  other  meats.11  Extracts 
of  yeast  are  much  less  active  than  meat-extract.12  The  latter 
shows  marked  influence,  too,  if  introduced  subcutaneously 
or  per  rectum.  It  is  scarcely  practicable  here  to  enter  into 
detailed  mention  of  the  action  of  the  great  mass  of  bitter 
stuffs,  alkaloids,  alcohol,  mineral  waters  and  neutral  salts 
upon  gastric  secretion  13 ;  but  in  actual  practice  all  these  sub- 
stances are  of  medicinal  interest  in  the  therapy  of  hyper- 
acidity and  hypersecretion.  It  is  but  fair  to  remark,  how- 
ever, that  in  this  connection  we  are  not  upon  safe  ground, 
particularly  as  many  of  the  affections  which  clinicians  have 
been  in  the  habit  of  classifying  under  the  terms  just  stated, 
should,  perhaps,  be  classed  as  disturbances  of  gastric  motil- 
ity, hyperesthesia  of  the  gastric  mucous  membrane  and 
other  comparable  conditions.14 

While  not  assuming  from  a  theoretical  standpoint  to 
enter  into  a  full  discussion  of  this  subject,  the  author  is 
unwilling  to  pass  over  a  group  of  other  factors  of  sig- 
nificant physiological  character,  of  importance  in  stimulat- 
ing secretion  of  the  gastric  juice.  An  attempt  has  been 
made  to  establish  a  relation  between  the  salivary  glands  and 
gastric  secretion,  from  the  circumstance  that  total  extirpa- 
ion  of  the  former  in  the  dog  has  seemingly  occasioned  a 
considerable  diminution  of  the  gastric  secretion  15 ;  but  the 
correctness  of  this  assertion  has  been  questioned.16 

Gastric  Secretin. — It  has  been  observed  that  when  neu- 
tralized gastric  juice  or  the  product  of  acid-extraction  of  the 
gastric  and  intestinal  mucous  membranes  and  of  many  other 

11  Cf.  B,  Lönnquist,  Skand.  Arch.  f.  Physiol.,  18,  194,  1906.  W.  N.  Boldy- 
reff,  Arch.  f.  Verdauungskr.,  15,  268,  1909. 

12  W.  Hoffmann  and  M.  Wintgen,  Arch.  f.  Hygiene,  61,  187,  1907. 
"Literature:    A.  Bickel,  Handb.  d.  Biochem.,  3',  66-69,  1910. 

14  Cf.  V.  Rubow,  Arch.  f.  Verdauungskr.,  12,  1,  1906;  R.  Kaufmann, 
Zeitschr.  f.  klin.  Med.,  57,  491,  1905. 

a  Hemmeter,  Biochem.  Zeitschr.,  11,  238,  1908. 

"A.  S.  Löwenhart  and  D.  R.  Hooker,  Proc.  Soc.  Exper.  Biol.,  5,  114,  1908. 


8  GASTRIC  DIGESTION  OF  PROTEINS 

tissues  is  introduced  subcutaneously  or  intravenously,  secre- 
tion of  gastric  juice  ensues.17  Bayliss  and  Starling  are  there- 
fore disposed  to  accept  the  existence  of  a '  *  gastric  secretin. ' ' 
According  to  this  view  the  normal  secretory  activity  of  the 
gastric  mucous  membrane  is  to  be  referred  to  two  factors : 
the  more  important  role  is  to  be  ascribed,  of  course,  to  the 
nervous  stimuli  transmitted  by  the  vagus  nerves ;  but  a  sec- 
ond influence,  determining  the  continuation  of  secretion  long 
after  the  influence  of  the  first  has  ceased,  is  held  to  be  an 
agency  of  chemical  nature.  This  is  believed  to  be  a  specific 
substance  generated  in  the  pyloric  mucous  membrane  under 
the  influence  of  acid,  which,  passing  into  the  blood,  is  returned 
to  the  mucous  membrane  of  the  stomach  as  a  "hormone"  or 
chemical  messenger,  stimulating  it  to  renewed  secretory 
activity.18  Discussion  of  the  hypothesis  is  postponed  to  the 
following  lecture  in  connection  with  the  subject  of  the  pan- 
creatic secretin. 

Inhibition  of  Secretion. — In  addition  to  those  influences 
which  induce  secretion  of  gastric  juice,  others  are  known 
which  act  to  inhibit  it,  an  example  being  manifested  in  the 
failure  to  secrete  following  the  introduction  of  fatty  foods 
into  the  stomach.  Pawlow  has  shown  that  the  inhibition  in 
such  case  arises  rather  from  the  duodenum  than  from  the 
stomach.  Apparently  alkalies  also  act  to  inhibit  the  secre- 
tion at  times  by  an  influence  arising  from  the  intestine. 
Attention  has  recently  been  called  by  clinicians  to  the 
absence  of  free  hydrochloric  acid  in  the  gastric  secretion  in 
cases  of  disease  of  the  gall-bladder,  and  to  the  value  of  this 
phenomenon  in  diagnosis.19 

Origin  of  Free  HCl  in  Mucous  Membrane  of  Stomach. — 
This  brings  us  again  to  the  old  problem  of  the  nature  of 

*  Edkins,  Jour,  of  Physiol.,  34,  133,  1906. 

"  E.  H.  Starling,  Lectures  on  Recent  Advances  in  the  Physiology  of  Diges- 
tion, p.  75,  et  seq.,  London,  1906;  W.  M.  Bayliss  and  E.  H.  Starling,  Ergebn. 
d.  Physiol.,  5,  676-677,  1906. 

19 H.  Hohlweg  (Voit's  Clinic  at  Giessen),  Deutsche  Arch.  f.  klin.  Med., 
108,  255,  1912. 


ORIGIN  OF  FREE  HCl  9 

the  particular  process  by  which  the  gastric  mucosa  is  enabled 
to  separate  a  free  mineral  acid  as  a  secretory  product.  There 
is  no  occasion  to  weary  the  reader  with  a  statement  of  the 
older  attempts  to  explain  the  phenomenon.  Neither  the 
idea  of  mass-action  of  carbonic  acid,  nor  that  of  alkali-binding 
by  lecithin-albumen,  nor  that  of  a  supposed  impermeability 
of  the  gastricmucous  membrane  to  chlorine  ions  has  withstood 
criticism 20 ;  and  it  has  been  impossible  to  find  in  the  mucous 
membrane  of  the  stomach  any  organic  compounds  of  chlorine 
from  the  dissociation  of  which  hydrochloric  acid  could  by 
any  possibility  be  produced.21  It  is  entirely  reasonable  to 
regard  the  sodium  chloride  of  the  ingested  food  as  the  source 
of  the  gastric  hydrochloric  acid.  Rosemann  has  established 
by  careful  investigation  the  fact  that  it  is  impossible  to  pro- 
duce any  important  reduction  of  the  chlorine  stored  in  the 
economy  by  starvation  and  the  use  of  food  poor  in  chlorine, 
because  the  system  is  able  to  protect  itself  against  chlorine 
impoverishment  by  lowering  the  excretion  of  chlorine  in  the 
urine  to  a  minimum.  It  is  possible,  of  course,  to  withdraw 
considerable  amounts  of  chlorine  from  the  body  by  "mock 
feeding"  because  of  the  hydrochloric  acid  secretion  thus  in- 
duced. In  the  end  secretion  of  fluid  ceases,  and  that,  too,  at 
a  time  when  the  general  body  still  contains  a  notable  amount 
of  chlorine.  Apparently  only  about  one-fifth  of  the  total 
chlorine  content  of  the  body  can  be  discharged  in  the  gastric 
secretion.22  From  studies  conducted  upon  a  professional 
female  starvationist  it  has  been  determined  that  even  after 
a  twenty-four  day  fast  the  stomach  will  respond  to  the 
stimulus  of  a  test-breakfast  by  production  of  a  fluid  which 

80  Cf.  L.  v.  Rhorer,  Pflüger's  Arch.,  150,  416,  1905. 

*  H.  Dauwe,  Arch.  f.  Verdauungskr.,  11,  137,  1905. 

aH.  Rosemann  (Münster),  Pflüger's  Arch.,  11^2,  208,  1911;  cf.  also  refer- 
ences of  J.  Wohlgemuth,  Exp.  Untersuchungen  über  den  Einfluss  des  Kochsalzes 
auf  den  Chlorgehalt  des  Magensaftes,  Berlin,  Hirschwald,  1906;  and  also  the 
older  investigations  of  Nencki,  Külz,  A.  Kahn  and  others. 


10  GASTRIC  DIGESTION  OF  PROTEINS 

while  showing  decided  lowering  of  the  hydrochloric  acid  is 
nevertheless  entirely  able  to  digest.23 

If  free  hydrochloric  acid  is  to  be  derived  from  sodium 
chloride,  the  latter  must  react  with  water  in  conformity  with 
the  equation:  NaCl  +  H20  =  NaOH  +  HCl.  For  each 
molecule  of  hydrochloric  acid  thus  separated  a  molecule  of 
sodium  hydroxide  must  remain  in  the  organism.  This  may 
explain  why  at  the  height  of  the  acid  secretion  the  sodium 
chloride  excretion  in  the  urine  is  diminished  and  why  in  the 
ensuing  period  of  resorption  of  the  strongly  acid  contents 
of  the  stomach  more  ammonia  fails  to  be  synthesized  into 
urea,  being  utilized  to  neutralize  the  free  acid.24  We  may 
conceive,  too,  why  the  body  of  an  animal  in  the  state  of 
chlorine  starvation  reacts  to  sodium  chloride  administration 
by  a  notable  increase  of  alkalinity  of  the  urine  (as  pointed 
out  by  the  author's  lamented  friend,  Leo  Schwarz,  in  Hof- 
meister's  laboratory  25).  The  fact  that  the  hydrochloric  acid 
of  the  gastric  juice  can  be  replaced  by  hydrobromic  acid  up 
to  a  certain  degree  indicates  that  sodium  bromide  acts  in  a 
comparable  manner. 

Physicochemical  Explanations. — Attempts  have  been  fre- 
quently made  to  apply  the  modern  ideas  of  physical  chem- 
istry to  the  problem  of  the  production  of  HCl  in  the  gastric 
juice.  When  the  ion  theory  began  slowly  to  penetrate  into 
the  minds  of  biologists  it  came  to  be  recognized  that  often  an 
explanation  may  be  realized  by  expressing  a  problem  in  the 
terms  of  the  theory  of  ions.  As  a  matter  of  fact,  as  you 
know,  if  to-day  a  problem  is  laid  before  the  great  public,  no 
matter  how  learnedly,  in  technical  phrases,  the  real  meaning 
is  no  more  grasped  than  if  it  had  been  told  in  the  Spanish  or 
Russian  language.    Unfortunately  here  and  there  we  can 

23  L.  Riitimeyer   (Basel),  Zentralbl.  f.  innere  Med.,  1909,  233. 

^A.  Müller  and  P.  S'axl  (I.  Med.  Clinic,  Vienna),  Zeitschr.  f.  klin.  Med., 
56,  546,  1905;  A.  Loeb  (Med.  Clinic,  S'trassburg ) ,  ibid.,  56,  1905;  S.  A.  Gam- 
meltoft  (Copenhagen),  Zeitschr.  f.  physiol.  Chemie,  75,  57,  1911. 

25 L.  Schwarz  (Physiol.  Chem.  Instit.,  Strassburg),  Hofmeister's  Beiträge, 
5,  56,  1903;  cf.,  ibid.,  also  the  work  of  Falck,  M.  Gruber,  and  Rosell. 


ACID-PRODUCTION  BY  MARINE  SNAILS  11 

still  find  in  modern  science  (especially  in  medicine)  some 
lingering  residuum  of  the  painstaking  endeavors  of  the  mas- 
ters of  the  Middle  Ages  to  impress  properly  the  audience 
with  the  fact  of  the  extreme  difficulty  of  understanding  their 
very  learned  disquisitions. 

However,  a  physicochemical  explanation  in  point  is  to 
be  found  in  the  proposition  which  Daneel  predicates  upon 
the  principle  of  ion  activity:  If  it  be  conceived  that  free 
organic  acids  are  produced  in  the  gastric  mucous  membrane 
(and  we  have  every  reason  for  assuming  that  the  production 
of  free  lactic  acid  is  a  function  common  to  cells  in  general, 
although  the  acid  is  quickly  neutralized  by  the  alkalies  of  the 
circulating  fluids),  we  may  represent  by  the  symbol  R 
an  organic  acid  radical;  and  the  dissociation  of  sodium 
chloride  and  of  acid  would  follow  the  formulas : 

NaCl  =  Na'  +  Cr 
HR    =H'     +  R'. 

Of  the  two  cations  H'  is  more  active  than  Na'  and  of  the 
anions  CI'  more  active  than  R' ;  wherefore  from  a  mixture 
of  sodium  chloride  and  organic  acid  it  is  possible  for  HCl 
to  form  by  diffusion,  as  if  the  stronger  mineral  acid  were 
driven  out  of  its  salt  by  the  much  weaker  organic  acid.  It 
would,  of  course,  not  be  difficult  for  any  physical  chemist 
to  raise  exception  to  this  method  of  explanation.  The 
author,  however,  has  a  constant  feeling  that  more  attention 
should  be  given  to  the  matter;  but  further  progress  in  the 
chemistry  of  colloids,  particularly  in  the  obscure  field  of  the 
phenomena  of  adsorption,  must  doubtless  be  attained  before 
the  subject  can  be  further  clarified. 

Acid-production  by  Marine  Snails. — In  this  place  it  is 
possible  only  in  the  briefest  manner  to  remind  the  reader 
that  the  gastric  production  of  acid  among  mam  tu  als  is  by 
no  means  an  isolated  phenomenon  of  this  sort  in  nature. 
When  Johannes  Müller  visited  Messina  in  1854  he  saw  with 
astonishment  that  a  streak  of  fluid  from  the  proboscis  of  the 


12  GASTRIC  DIGESTION  OF  PROTEINS 

large  "partridge-shell"  snail,  Dolium  galea,  on  coming  in 
contact  with  the  marble  tiles  with  which  the  room  was  paved, 
caused  an  effervescence  just  as  if  some  strong  acid  had  been 
dropped  upon  the  tile.  Since  then  we  have  come  to  know 
that  a  number  of  marine  snails  secrete  an  acid  salivary  fluid, 
and  that  that  of  Dolium  contains  appreciable  amounts  of 
free  sulphuric  acid.26 

Determination  of  Acidity  of  Gastric  Juice. — In  any 
observation  relative  to  acid  secretion  in  the  gastric  juice 
the  quantitative  determination  of  the  free  hydrochloric 
acid  is  naturally  a  matter  of  much  importance;  some  of 
the  more  definite  advancements  of  method  deserving  brief 
mention  at  this  time.  A  number  of  new  features  have  been 
added  to  the  old  color  reactions  for  the  recognition  of  free 
hydrochloric  acid,  as  the  employment  in  modification  of 
Günzberg's  reagent  of  a  mixture  of  p-oxybenzaldehyde  with 
phloroglucin  or  of  a  mixture  of  dimethylamidobenzaldehyde 
with  indol.  It  is  of  more  importance,  however,  that  we 
have  come  to  recognize  that  estimation  of  the  true  acidity 
of  the  gastric  juice,  that  is,  its  hydrogen  ion  concentration,  is 
impossible  by  simple  titration.  For  this  we  need  either 
measurement  of  the  electromotor  power  of  the  actual 
hydrogen-concentration  chains  27  or  the  indicator  method. 
In  Müller 's  method  gastric  juice  is  mixed  with  a  solution  of 
tropaeolin ;  the  fluid  then  assumes  a  color,  which  ranges  ac- 
cording to  the  degree  of  acidity  between  a  reddish  brown  and 
yellow,  and  by  comparison  with  a  color  scale  the  percentage 
presence  of  "free  hydrochloric  acid"  can  be  directly  de- 
termined.28    The  method  of  Dreser  29  is  based  on  quite  a 

26  Literature  upon  Acid  Secretion  in  Gastropoda :  O.  v.  Fürth,  Ver 
gleichende  chemische  Physiologie  der  niederen  Tiere,  pp.  208-215,  Jena,  1903 

27  C.  Foft,  C.  R.  Soc.  de  Biol.,  1905,  I,  865;  II,  2;  F.  Tangl,  Pflüger's  Arch. 
115,  64,  1906.  L.  Michaelis  and  H.  Davidsohn,  Zeitschr.  f.  exper.  Pathol.  8 
398,  1910;  J.  Christiansen  (Copenhagen),  Deutsche  Arch.  f.  klin.  Med.,  102 
103,  1911. 

28 A.  Müller  (Clinic  of  v.  Noorden,  Vienna),  Med.  Klinik,  1909,  1438. 

28  H.  Dreser,  Hofmeister's  Beitr.,  8,  285,  1906. 


BINDING  OF  THE  HYDROCHLORIC  ACID  13 

different  principle.  An  excess  of  relatively  insoluble  barium 
oxalate  is  added  to  the  gastric  juice  as  "ground  substance" 
and  the  quantity  of  oxalic  acid  thrown  into  solution  by  the 
hydrochloric  acid  is  estimated  by  titration  with  potassium 
permanganate.  In  another  test 30  the  amount  of  iodine  freed 
from  a  mixture  of  potassium  iodide  and  potassium  iodate  in 
the  presence  of  hydrochloric  acid  is  determined  by  titration 
and  used  as  measure  of  the  latter.  The  test  proposed  by 
Holmgren31  is  particularly  original;  it  is  based  upon  the 
adsorption  of  acids  in  capillary  media.  If  an  acid  solution 
is  allowed  to  drop  from  a  pipette  upon  a  filter  paper  spread 
out  horizontally  it  will  be  observed  that,  as  the  drop  spreads 
out  circularly,  only  the  central  part  of  the  moist  circle  shows 
an  acid  reaction,  the  peripheral  part  containing  nothing  but 
water.  The  acid  moieties  are  thus  more  freely  adsorbed  by 
the  filter  paper  than  the  water  molecules.  And  it  has  been 
shown  that  the  more  concentrated  the  acid  the  narrower  the 
acid-free  ring  at  the  margin;  and  that  the  surface  of  the 
central  circular  acid  area  and  that  of  the  peripheral  acid-free 
zone  vary  in  relation  to  each  other,  according  to  the  acidity 
of  the  solution  employed.  The  outcome  is  strikingly  regu- 
lar, and  the  results  may  be  obtained  almost  at  a  glance  if  the 
paper  used  has  been  colored  with  litmus ;  and  the  test,  car- 
ried out  in  a  very  few  moments,  accords  a  fairly  delicate  esti- 
mate for  practical  purposes  of  the  acidity  of  a  sample  of 
gastric  juice.  A  very  small  quantity  of  the  latter,  about 
one-tenth  of  a  cubic  centimeter,  serves  for  the  determination. 
Binding  of  the  Hydrochloric  Acid  by  Protein  Bodies. — 
There  is  no  lack  of  methods,  it  is  true,  for  the  determina- 
tion of  the  free  hydrochloric  acid  in  the  gastric  juice ;  but 
the  question  then  comes  up  as  to  what  can  be  the  particular 
value  of  them  at  best.  For  it  must  be  confessed  that  the 
importance  of  determining  free  hydrochloric  acid,  especially 

30 M.  Wegrumba    (Berne),  Internat.  Beitr.  z.  Pathol,  u.  Ther.  d.  Ernäh- 
rungsstörungen, 3,  53,  1911. 

81  J.  Holmgren  (Stockholm),  Deutsche  med.  Wochenschr.,  1911,  247. 


14  GASTRIC  DIGESTION  OF  PROTEINS 

for  clinical  purposes,  has  been  very  much  overestimated. 
The  actual  facts  may  from  a  practical  standpoint  be  stated 
without  hesitation  as  follows :  The  free  hydrochloric  acid  of 
the  gastric  juice  in  the  presence  of  albuminous  food  is 
quickly  linked  either  completely  or  partly  to  the  proteins  or 
their  cleavage  products.  It  should  be  kept  in  mind  that 
proteins  are  such  weak  bases  that  their  salts  are  open 
to  extensive  hydrolytic  dissociation32 — so  much  so  that  in 
dissolving  them  a  part  only  of  a  given  protein-salt  remains 
as  such,  the  remainder  reverting  at  once  to  protein  and 
free  hydrochloric  acid.  The  old  belief  was  that  the  free 
acid  alone  had  any  important  bearing  upon  the  digestion, 
and  it  was  for  this  reason  that  so  much  stress  was  laid  upon 
its  estimation.33  It  was  doubted,  for  example,  because  the 
measurement  of  the  concentration  of  hydrogen-ions  in  the 
infant's  stomach  showed  only  very  low  tension,  whether  the 
pepsin  here  could  have  as  its  chief  function  a  digestive  ac- 
tivity or  whether  it  would  not  much  more  likely  act  as  a  lab 
ferment.34  It  seems  important  that,  as  Julius  Schütz 
demonstrated,  the  presence  of  H-ions  is  not  absolutely 
necessary  for  peptic  digestion;  the  process  begins  at  once 
in  the  presence  of  no  more  than  a  very  small  amount  of 
combined  acid  (hydrochloric  acid  linked  to  albumin). 
Schütz  believes  that  the  principal  purpose  of  the  excessive 
(i.e.,  "free")  hydrochloric  acid  is  probably  to  protect  the 
native  proteins  from  loss  of  the  hydrochloric  acid  linked  to 
them  which  the  proteid  catabolic  products  arising  in  the 
course  of  digestion  endeavor  to  abstract;  that  therefore  it 
is  no  more  than  a  reserve  stock.  From  this  point  of  view 
it  is  not  the  relative  concentration  but  the  absolute  quantity 
of  free  acid  present  which  should  stand  as  a  measure  of  the 

33  Literature:    O.  Cohnheim,  Nagel's  Handb.  d.  Physiol.,  2,  543-547,  1907. 
8SCi.  A.  Müller    (I.  Med.  Clinic,  Vienna),  Deutsche  Arch.  f.  klin.  Med., 

94,  27,  1908. 

34  H.  Davidsohn,  Zeitschr.  f.  Kinderheilk.,  2,  420,  1911. 


PROTEIN  DIGESTION  IN  THE  STOMACH  15 

intensity  of  the  digestive  process.35  Then,  too,  there  exist 
very  suggestive  observations  indicative  of  the  impossibility 
of  obtaining  by  distillation  free  hydrochloric  acid  from  gas- 
tric juice  during  active  digestion.36  In  contradistinction  to 
this  idea  there  are,  of  course,  other  authors  who  insist  that 
the  presence  of  free  hydrochloric  acid  is  absolutely  essential 
for  thorough  utilization  of  the  food.37 

Extent  of  Protein  Digestion  in  the  Stomach. — Let  us 
now  turn  to  the  question  as  to  the  extent  to  which  pro- 
tein digestion  actually  takes  place  in  the  stomach  and  the 
catabolic  products  which  are  normally  produced  there.  This 
subject  has  been  so  well  worked  out  that  the  actual  facts  of 
the  matter  can  be  stated  very  briefly,  even  though  the  litera- 
ture thereupon  is  extensive.38  This  is  due  primarily  to  the 
labors  of  Edgard  Zunz,  of  Brussels,39  conducted  by  him  with 
much  success  through  a  long  series  of  years,  and  also  to  the 
united  work  of  London  and  Abderhalden  40  and  their  numer- 
ous collaborators,  their  studies  combining  happily  the  most 
advanced  ideas  of  a  finished  fistula-technique  with  those  of 
the  chemistry  of  proteins. 

"The  coagulated  proteins  of  meat,"  to  quote  E.  Zunz, 
writing  about  ten  years  ago,41  "are  in  turn  dissolved  in  the 

35  J.  Schütz,  Wiener  med.  Woehenschr.,  1906,  Nos.  41  and  42;  Biochem. 
Zeitschr.,  22,  33,  1909;  Arch.  f.  Verdauungskr.,  11,  11,  1911;  note  Literature 
in  latter  article;  cf.,  also,  H.  Jastrowitz  (Siegfried's  Lab.),  Biochem.  Zeitschr., 
2,  157,  1906. 

30  F.  Landolph,  Nouvelles  etudes  chimiques  sur  le  sue  gastrique :  Buenos 
Aires,  1911;    Zentralbl.  f.  Physiol.,  25,  539,  1911. 

37  Cf.  G.  Ewald  (Med.  Clinic,  Erlangen),  Deutsche  Arch.  f.  klin.  Med., 
106,  498,  1912. 

88  Literature  upon  the  extent  of  gastric  digestion:  E.  Zunz,  Ergebn.  d. 
Physiol.,  5,  622-663,  1906;    E.  S.  London,  Handb.  d.  Biochemie,  3",  68-80,  1909. 

39  E.  Zunz,  1.  c.  and  Bulletin  de  la  Soci£te  roy.  des  Sciences  med.  et  natur. 
de  Bruxelles,  1910,  No.  3;  Memoires  couronnes  et  autres  memoires  publies  par 
lAcad.  roy.  de  med.  de  Belgique,  19,  3,  1906;  20,  1,  1908;  Bull,  de  lAcad.  roy. 
de  med.  de  Belgique,  2Jf,  241,  1910;   abstracted  in  Jahresb.  f.  Tierchem.,  1^0,  371. 

40  E.  Abderhalden  and  E.  S.  London,  together  with  K.  Kautsch,  L.  Baumann, 
O.  Prym,  K.  v.  Körösy,  C.  Vögtlin,  Zeitschr.  f.  physiol.  Chem.,  48,  549,  1906; 
51,  383,  1907;    53,  147,  343,  1907. 

41 E.  Zunz,  Hofmeister's  Beitr.,  3,  339,  1902. 


16  GASTRIC  DIGESTION  OF  PROTEINS 

stomach  by  the  gastric  juice,  in  which  process  there  arise 
a  very  small  proportion  of  acid-albumin,  a  large  quantity 
of  albumoses  and  a  smaller  quantity  of  more  advanced  diges- 
tive products  (peptone,  peptoids,  and  perhaps  some  of  the 
crystallizable  end-products).  The  portion  which  has  been 
dissolved  passes  for  the  most  part  into  the  small  intestine, 
where  it  rapidly  undergoes  further  dissociation  and  resorp- 
tion. A  small  residue  is  resorbed  directly  in  the  stomach ; 
the  advanced  products  of  digestion  are  next  to  be  absorbed, 
while  albumoses  are  taken  up  with  difficulty."  The  author 
has  in  a  previous  volume  (Vol.  I  of  this  series,  p.  77,  et  seq., 
The  Chemistry  of  the  Tissues)  taken  occasion  to  indicate  the 
change  of  view  which  has  arisen  within  the  past  decade  in  re- 
spect to  the  albumoses,  which  in  strict  parlance  are  no  longer 
accepted.  The  schematic  tables  of  the  sequence  of  the 
various  types  of  ' '  albumoses ' '  and ' '  peptones ' '  in  the  course 
of  gastric  digestion,  on  which  so  much  time  and  labor  used 
to  be  expended,  have  today  become  practically  meaningless. 
But  it  is  important,  as  established  by  Abderhalden  and  Lon- 
don,, that  cleavage  of  aminoacids  from  the  protein  molecule 
scarcely  occurs  at  all  in  the  stomach,  as,  too,  that  synthetic 
Polypeptids  supplied  are  not  appreciably  affected.42  The 
velocity  of  solution  depends  upon  the  nature  of  the  protein 
(for  instance,  gelatine  is  " digested"  much  more  rapidly 
than  serum-albumin  or  egg-albumin).  The  dissolved  pro- 
teins of  the  gastric  contents  correspond  for  the  most  part  to 
the  old  definition  of ' '  albumoses. ' '  Another  important  mat- 
ter is  the  rapidity  of  passage  of  the  dissolved  material  in 
the  stomach  into  the  intestine.  It  has  been  long  known  that 
the  degree  of  coagulation  of  the  proteins  is  here  an  impor- 
tant matter  and  that  it  makes  decided  difference  whether 
they  are  ingested  raw  or  cooked.  There  are,  moreover, 
other  items  not  well  understood.  For  example,  while  raw 
egg-albumin  has  left  a  dog's  stomach,  for  the  most  part 

42  E.  Abderhalden  and  E.  S.  London,  1.  c. 


PROTEIN  DIGESTION  IN  THE  STOMACH  17 

changed,  within  but  little  more  than  an  hour,  raw  meat  is 
retained  for  considerably  longer  time.43 

The  resorption  of  the  products  of  protein  cleavage  in  the 
stomach  is  always  of  very  minor  importance.  Meat  and 
albumin  leave  the  stomach  of  the  dog,  according  to  London, 
without  having  undergone  any  notable  nitrogenous  resorp- 
tion. Moreover,  the  products  of  protein  catabolism,  which 
are  readily  absorbed  in  the  intestine,  can  be  quantitatively 
recovered  if  in  the  stomach  even  for  a  number  of  hours.  (It 
is  true,  however,  that  Salaskin,  in  agreement  with  the  older 
views,  insists  upon  the  actual  absorption  of  protein  sub- 
stances in  the  stomach.)  44 

In  this  connection  the  reduced  ability  of  proteins  which 
have  been  acted  upon  by  pepsin  and  hydrochloric  acid  to 
withstand  the  subsequent  action  of  trypsin,  as  pointed  out 
by  Carl  Oppenheimer  and  Aron  45  and  by  Emil  Fischer  and 
Abderhalden 46  has  important  physiological  bearing. 

As  the  gastric  function  in  protein  digestion  therefore  is 
in  a  general  way  a  preparatoiy  one  it  cannot  be  regarded  as 
a  very  wonderful  thing  that  it  has  been  found  possible  to 
perform  complete  gastrectomy  in  animals  and  in  man,  since 
the  well-known  experiments  of  Karl  Ludwig  and  Ogata  and 
the  actual  total  extirpation  of  the  human  stomach  by 
Czerny.47 

As  to  the  extent  of  resorption,  opinions  vary  widely. 
While  London,  as  above  stated,  regards  it  as  of  little  conse- 
quence, Scheunert 48  accepts  for  the  stomach  a  fixed  power  of 
absorption  as  proved  (basing  his  opinion  upon  the  observa- 

18  E.  S.  London,  with  W.  Polowzowa,  A.  Th.  Sulima,  C.  Schwarz,  Zeitschr. 
f.  physiol.  Chemie.,  46,  209,  1905;    49,  328,  1906;    68,  378,  1910. 

**S.  Salaskin,  Zeitschr.  f.  physiol.  Chem.,  51,  167,  1907. 

"  C.  Oppenheimer  and  H.  Aron,  Hofmeister's  Beitr.,  4,  279,  1903. 

"  E.  Fischer  and  E.  Abderhalden,  Zeitschr.  f.  physiol.  Chem.,  40,  215,  1903. 

*'  M.  Ogata,  G.  Carvallo  and  V.  Pachon,  Langenbuch,  C.  Schlatter ;  also 
A.  Carrel,  G.  M.  Meyer  and  P.  A.  Levene,  Amer.  Jour,  of  Physiol.,  26,  369,  1910; 
E.  S.  London  and  W.  F.  Dagaew,  Zeitschr.  f.  physiol.  Chem.,  14,  330,  1911. 

"A.  Scheunert,  Zeitschr.  f.  physiol.  Chem.,  51,  519,  1907. 
2 


18  GASTRIC  DIGESTION  OF  PROTEINS 

tions  of  Lang  and  Tobler,  as  well  as  his  own,  upon  horses 
and  dogs). 

Comparative  Physiological  Considerations. — Our  view 
of  physiological  processes  of  any  sort  is  bound  to  be  un- 
duly warped  and  limited  if  we  confine  ourselves  to 
human  beings  and  the  ordinary  laboratory  experiment  ani- 
mals. Nothing  less  than  a  consideration  of  all  classes  of 
life  forms  can  assure  a  thoroughly  scientific  basis.  William 
Biedermann  49  by  the  monumental  work  in  which  he  has 
collected  and  critically  dealt  with  the  whole  mass  of  material 
bearing  on  digestion  from  the  standpoint  of  comparative 
physiology,  has  certainly  earned  a  claim  to  general  gratitude 
from  all  who  are  concerned  with  biological  studies.  The 
author  feels  that  at  least  a  few  brief  considerations  should 
be  given  to  this  side  of  the  subject,  restricting  himself,  how- 
ever, to  the  vertebrates  because  he  has  elsewhere  dealt  with 
the  chemistry  of  digestion  in  invertebrates.50 

In  the  first  place,  among  fishes  51  there  occur  forms  with- 
out stomachs  (among  others,  amphioxus,  the  cyclostomata 
and  cyprinoids).  In  the  cyprinoid  fishes  the  opening  of  the 
gall  duct  lies  just  back  of  the  oesophageal  opening  into  the 
intestine;  and,  of  course,  it  is  impossible  that  in  such  case 
there  could  be  the  least  trace  of  gastric  digestion  in  its 
ordinary  meaning.  Most  fishes,  however,  possess  a  stom- 
ach, the  glands  of  which  secrete  an  enzyme  capable  of  digest- 
ing protein  substance  in  an  acid  reaction.  The  most  exact 
work  in  this  connection  has  been  done  upon  the  selachians. 
There  is  divergence  of  opinion  as  to  the  existence  of  free 
hydrochloric  acid  in  the  gastric  juice  of  sharks  (recently 

49  W.  Biedermann,  Handb.  d.  vergl.  Physiol.,  H.  Winterstein,  2'  (Die 
Aufnahme,  Verarbeitung  und  Assimilation  der  Nahrung,  pp.  1563,  Jena,  1911). 

60  O.  v.  Fürth,  Vergleichende  chemische  Physiologie  der  niederen  Tiere, 
pp.  140-330,  Jena,  1903. 

61  Literature  upon  gastric  digestion  in  fish :  A.  Scheunert,  Handb.  d. 
Biochem.,  3",  163-167,  1909;  W.  Biedermann,  1.  c,  pp.  1088-1106;  cf.  also 
D.  D.  Van  Slyke  and  G.  F.  White,  Journ.  of  Biol.  Chem.,  9,  209,  1911. 


PHYSIOLOGICAL  CONSIDERATIONS  19 

discussed  by  E.  Weinland  and  by  M.  van  Herwerden)  52  but 
for  that  matter  the  entire  question  is  of  lessened  importance, 
since  we  have  come  to  recognize  the  positive  influence  of  com- 
bined hydrochloric  acid  in  peptic  digestion  (v.  sup.).  Be- 
sides, the  pepsin  of  fishes  apparently  is  not  entirely  identical 
with  that  of  the  mammalia. 

Gastric  digestion  in  amphibia,  reptiles  and  birds  53  cor- 
responds doubtless  with  the  peptic  type.  In  graminivorous 
birds,  whose  food  is  first  acted  upon  in  a  crop,  the  peptic 
catabolism  of  protein  may  begin  even  in  this  organ. 

From  the  point  of  systematic  investigation  of  the  com- 
parative physiology  of  digestion  in  mammals  54  Ellenberger 
and  Scheunert,  scientists  in  the  Veterinary  High  School  in 
Dresden,  have  rendered  most  important  service.  In  the 
ruminants,  with  three  complex  proventricles  preceding  the 
glandular  stomach,  it  goes  without  saying  that  complicated 
processes  of  digestion  are  met.  The  hamster  with  its  two- 
chambered  stomach  presents  interesting  features,  the  first 
lined  with  a  cutaneous  type  of  mucous  membrane  and  con- 
nected by  a  very  narrow  opening  with  the  glandular  stomach 
proper,  thus  occupying  an  intermediate  position  between  the 
many-chambered  stomach  of  the  ruminants  and  the  single- 
chambered  stomach  of  the  solipeds,  the  hog  and  other 
mammals.  The  digestion  of  the  food  proteins  by  the  gastric 
juice  takes  place  only  in  the  gland-bearing  stomach,  while 

52  M.  van  Herwerden  (Physiol.  Institut.,  Utrecht),  Zeitschr.  f.  physiol. 
Chem.,  56,  453,  1908;    E.  Weinland,  Zeitschr.  f.  Biol.,  55,  58,  1911. 

"Literature  upon  gastric  digestion  in  Amphibia,  Reptiles  and  Birds:  A. 
Scheunert,  Handb.  d.  Biochem.,  3",  168-170,  1909;  W.  Biedermann,  1.  c,  pp. 
1272-1281. 

w  Literature  upon  the  comparative  physiology  of  gastric  digestion  in 
Mammalia:  A.  Scheunert,  Handb.  d.  Biochem.,  3",  153-162,  1909;  W.  Bieder- 
mann, 1.  c,  pp.  1299-1311;  W.  Ellenberger  and  A.  Scheunert,  Lehrb.  d.  vergl. 
Physiol.,  Berlin,  P.  Parey,  1910;  A.  Scheunert,  Vergleichende  Studien  über  den 
Eiweiszabbau  im  Magen,  O.  Wallach,  Festchrift,  Göttingen,  1909;  and  Pflüger's 
Arch.,  109,  145,  1905,  and  139,  131,  1911;  A.  Scheunert  and  E.  Rosenfeld, 
Deutsche  tierärztl.  Wochenschr.,  11,  No.  25;  A.  Scheunert.  and  W.  Grimmer, 
Zeitschr.  f.  physiol.  Chem.,  58,  27,  1906;  E.  Rosenfeld,  Inaug.  Diss.,  Leipzig, 
1908;  A.  Schattke,  Inaug.  Diss.,  Dresden,  1909;  F.  Bengen  and  G.  Haane, 
Pflüger's  Arch.,  106,  267,  286,  1905. 


20  GASTRIC  DIGESTION  OF  PROTEINS 

in  the  proventricle  processes  of  bacterial  decomposition  of 
the  proteins  may  be  in  play.  However,  even  in  animals  with 
simple  stomachs  the  details  of  the  process  may  show  vari- 
ations. For  example,  in  the  dog,  as  above  mentioned,  the 
proteid  catabolic  products  arising  in  the  stomach  consist  for 
the  most  part  of  albumoses ;  while  in  the  horse  the  quantity 
of  albumoses  is  never  marked  enough  to  permit  their  pre- 
dominance over  syntonins,  peptones  and  abiuret  products. 

At  this  point  we  may  take  up  at  least  briefly  a  considera- 
tion of  the  digestive  ferment  of  the  stomach,  pepsin.™ 

Efforts  to  Isolate  Pepsin. — A  great  deal  of  effort  has  been 
expended  in  attempts  to  isolate  pepsin,56  and  an  apparently 
albumin-free  ferment  has  a  number  of  times  been  obtained, 
although  usually  it  is  thrown  down  along  with  other  precipi- 
tates of  extremely  varied  types.  Thus  in  Hofmeister 's  labo- 
ratory 57  a  pepsin,  "albumin-free"  in  the  ordinary  sense,  has 
been  produced  by  expression  by  aBuchner  press  from  gastric 
mucous  membrane  ground  up  with  infusorial  earth,  nitration 
of  the  fluid  through  a  Chamberland  filter,  subsequent  dialysa- 
tion  (Brücke's  method),  and  displaced  with  an  alcohol-ether 
solution  of  Cholesterin.  The  pepsin  adheres  to  the  separat- 
ing Cholesterin  precipitate.  By  suspending  the  latter  in 
water  and  removing  the  Cholesterin  with  ether,  there  re- 
mains a  clear  fluid  with  active  digestive  power  failing  to 
show  protein  reaction  or  lab  activity.  These  occasionally 
recurring  efforts  to  produce  "analytically  pure"  pepsin  are 
growing  more  and  more  infrequent,  as  it  is  gradually  being 
appreciated  that  at  best  it  is  a  fruitless  labor.  Even  if  in  the 
end,  after  much  care  and  effort,  a  ferment  is  obtained  so  thor- 
oughly isolated  that  a  protein  reaction  can  no  longer  be 

66  Literature  upon  pepsin :  A.  Cohnheim,  Nagel' s  Handb.  d.  Physiol.,  2, 
548-552,  1907;  F.  Samuely,  Handb.  d.  Biochem.,  1,  546,  1909;  A.  Bickel,  ibid., 
8\  100,  1910;  C.  Oppenheimer,  Fermente,  III.  Aufl.,  256-280,  1910;  W.  Bieder- 
mann, 2,  I.  Hälfte/ 1257-1264,  1911. 

68  Recent  experiments  of  Sundberg,  Sjöquist,  Mrs.  Schoumow-Simonowsky, 
Friedenthal,  Pekelharing,  Schrumpf  and  others. 

"  P.  S'cbrurnpf,  Hofmeister's  Beitr,,  6,  396,  1905. 


METHODS  FOR  ESTIMATION  OF  PEPSIN  21 

obtained  there  is  bound  to  remain  the  objection  that  this 
means  nothing  more  than  that  enzyme  action  may  continue 
in  degrees  of  dilution  in  which  the  most  delicate  reactions 
fail  to  show  protein.  It  is  utterly  impossible  for  any  man 
at  the  present  time  to  say  whether  the  ferments  are  of  a 
proteid  nature  or  not.  When  a  French  physiologist  gave  it 
as  his  opinion  that  ferments  are  in  no  sense  material,  but 
energy  alone,  his  statement  called  forth  vehement  opposi- 
tion. To-day,  however,  when  a  slow  but  sure  change  is 
taking  place  in  our  fundamental  ideas  about  atoms,  and  the 
very  basis  of  our  older  conception  of  nature,  the  duality  of 
matter  and  force,  is  decidedly  wavering,  such  heretical 
theories  would  scarcely  excite  anything  like  the  same 
indignation. 

Methods  for  Estimation  of  Pepsin. — Numerous  methods 
have  been  applied  to  the  quantitative  determination  of 
pepsin.  Grützner  estimates  the  amount  of  coloring  mat- 
ter passing  into  solution  in  the  digestion  of  fibrin  stained 
with  carmine,  using  a  wedge-colorimeter.58  In  Mett's 
method  the  length  of  a  column  of  coagulated  albumin 
enclosed  in  a  fine  glass  tube  is  measured  after  a  fixed  period 
of  digestion.  Hammerschlag  estimates  by  precipitation 
with  Esbach's  reagent  the  amount  of  undigested  protein 
remaining  after  digestion  of  a  known  albumin  solution  for  a 
certain  fixed  time.  Spriggs  tries  to  draw  a  conclusion  from 
the  loss  of  viscosity  of  a  protein  solution  as  to  the  progress 
of  its  digestion.  Vollhard  begins  with  a  known  solution  of 
casein ;  throws  out  the  undigested  casein  by  sodium  sulphate, 
and  estimates  the  amount  of  digested  protein  in  the  filtrate 
by  its  alkali-binding  power  determinable  by  titration :  the 
more  advanced  the  digestion  the  more  potassium  or  sodium 
hydrate  required.  E.  Fuld  arranges  a  series  of  small 
beakers  each  containing  the  same  quantity  of  a  hydrochloric 
acid  solution  of  a  pure  protein,  edestin,  adding  graduated 
quantities  of  the  solution  whose  peptic  quantity  is  to  be 

88  P.  v.  Grützner  (Tübingen),  Pflüger's  Arch.,  IM,  545,  1912. 


22  GASTRIC  DIGESTION  OF  PROTEINS 

determined;  after  appropriate  time  for  digestion  sodium 
chloride  is  added  to  all  of  the  samples,  and  the  result  esti- 
mated by  the  degree  of  turbidity  ensuing  (absent  in  fully 
digested  specimens).  M.  Jacoby  and  Solms  substitute  ricin 
for  edestin;  Gross  casein;  and  Eose  protein  (globulin)  of 
garden-pea  in  modification  of  the  latter  method.59 

Law  of  Pepsin  Fermentation. — Based  upon  these 
methods  it  has  been  thought  possible  to  establish  a  "  fer- 
mentation law"  for  the  activity  of  pepsin.  The  Schiitz- 
Borissow  rule,  making  the  effectiveness  of  the  pepsin 
proportionate  to  the  fourth  root  of  its  quantity,  has  at- 
tained considerable  popularity  and  has  been  very  much 
discussed.60  Without  going  into  the  details  of  ferment 
activity  it  may  be  stated  that  P.  v.  Grützner 61  has  concluded 
from  his  careful  and  critical  studies  in  reference  to  pepsin 
and  trypsin  ' '  that  there  is  no  uniform  law  prevailing  during 
the  entire  course  of  a  process.  ...  In  the  processes  of 
digestive  fermentation  at  the  beginning  one  rule  prevails, 
which  is  not  the  same  for  the  intermediate  stage  or  for  the 
terminal  part.  Moreover,  as  stated,  the  absolute  and  rela- 
tive quantity  of  a  ferment  will  cause  variation  of  the  law  and 
it  is  impossible  to  speak  of  a  law  in  the  usual  meaning  of 
the  term  for  any  one  ferment. ' ' 

Propepsin. — Pepsin  does  not  exist  in  completed  state  in 
the  glands  of  the  gastric  mucosa,  as  shown  by  the  studies  of 
Ebstein  and  Grützner  and  those  of  Langley,  but  in  the  form 
of  a  proferment  which  (in  contrast  to  pepsin,  which  is  very 
sensitive  to  alkalies)  is  resistant  to  alkali,  and  immediately 
changes  into  pepsin  when  brought  in  contact  with  hydro- 

58  Cf.  critique  of  methods,  P.  v.  Grützner  (Festschr.  f.  G.  Fano),  Arch,  di 
Fisiol.,  7,  223,  1909;  E.  Henrotin,  Ann.  de  la  Soc.  roy.  des  Sciences  mod.  et 
natur.  de  Bruxelles,  18,  fasc,  2,  1908;  W.  C.  Rose,  Arclr.  of  Intern.  Med.,  5, 
459,  1910;  A.  Fubini,  Gaz.  Osped.,  30,  409,  1909;  P.  W.  Cobb  (Cleveland), 
Amer.  Journ.  of  Physiol.,  13,  448,  1905. 

60  Cf.  J.  Schütz  (Laborat.  Hofmeister),  Zeitschr.  f.  physiol.  Chem.,  30,  1, 
1900;  Reichel,  Wiener  klin.  Wochenschr.,  1908,  No.  30. 

64  P.  v.  Grützner,  Pfliiger's  Arch.,  l.'fl,  115,  1911. 


RESISTANCE  OF  STOMACH  TO  AUTODIGESTION      23 

chloric  acid.  Glässner 62  has  succeeded  in  separating  pro- 
pepsin from  labproferment  by  precipitation  with  uranyl 
acetate. 

Psendopepsin. — The  existence  of  a  pseudo pepsin,  ob- 
tained from  the  pyloric  mucous  membrane  by  the  investi- 
gator mentioned,  said  to  act  under  weakly  alkaline  reaction 
and  to  split  protein  with  production  of  tryptophane,  is  a 
matter  of  considerable  doubt;  as  in  the  first  place  it  can 
scarcely  be  distinguished  from  autolytic  tissue  enzymes  and, 
as  is  well  known,  the  entrance  of  trypsin  into  the  pylorus  is 
not  an  infrequent  occurrence.63 

Passage  of  Pepsin  into  the  Intestinal  Canal. — Abder- 
halden has  made  interesting  observations  showing  the 
marked  readiness  with  which  pepsin  is  taken  up  by 
elastin  and  similar  substances.  The  pepsin  may  be  practi- 
cally all  removed  from  the  gastric  juice  by  means  of  elastin. 
Protected  within  such  albuminoids  the  enzyme  may  be  car- 
ried into  the  intestine  and  there  complete  its  action.  Con- 
siderable amounts  of  active  pepsin  have  been  detected  in  the 
upper  portion  of  the  intestine  by  the  elastin  method ;  and 
apparently  peptic  digestion  is  not  limited  entirely  to  the 
stomach,  but  plays  an  important  role  in  the  intestine  as 
well.64 

Resistance  of  Stomach  to  Autodigestion. — The  physi- 
ology of  gastric  digestion  includes  another  problem  which 
has  long  stimulated  investigation  in  a  marked  degree. 
This  concerns  the  method  of  protection  of  the  digestive 
organs  against  self-digestion.  Every  thoughtful  person 
who  has  ever  noticed  the  rapidity  with  which  a  bit  of  albumin 
is  digested  by  active  gastric  juice,  has  necessarily  asked  him- 

°K.  Glässner,  Hofmeister's  Beitr.,  1,  24,  1901. 

"*  Cf.  the  publications  of  F.  Klug,  A.  Scheunert  and  Grimmer,  Pekelharing 
(cited  in  Handb.  d.  Biochem.,  1,  551,  1909)  and  F.  Reach  (Hofmeister's  Beitr., 
h,  143,  1903). 

**  E.  Abderhalden  in  association  with  F.  W.  Strauch,  F.  Wachsmuth,  O. 
Meyer  and  K.  Kiesewetter,  Zeitschr.  f.  physiol.  Chem.,  71,  314,  339,  1911;  H, 
67,  411,  1911. 


24  GASTRIC  DIGESTION  OF  PROTEINS 

self  how  it  is  that  the  mucosa  of  the  living  human  and  animal 
stomach  is  able  to  withstand  the  peptic  action  of  the  gastric 
juice.  As  early  as  in  the  eighteenth  century  Hunter  was 
searching  for  an  answer  to  this  question ;  and  ever  since  the 
great  Claude  Bernard  interested  himself  in  it  it  has  never 
been  dropped  from  the  list  of  the  day's  work  awaiting  the 
physiologist.65 

The  author  has  in  an  earlier  volume  taken  up  the  discus- 
sion of  anti-ferments  (in  the  first  volume  of  this  series,  p. 
559,  Chemistry  of  the  Tissues).  Following  A.  Danilewski's 
demonstration  of  the  existence  of  an  antipepsin  in  the  lining 
of  the  stomach  and  that  of  Ernst  Weinland 66  proving  the 
resistance  of  parasitic  worms  to  the  gastric  and  intestinal 
ferments  from  this  standpoint,  numerous  investigations  have 
been  made  upon  the  subject.  A  diffusible  agent  has  been 
found  in  the  gastric  juice  which  withstands  heating,  is  re- 
sistant to  acids  and  alkalies  and  is  capable  of  inhibiting 
peptic  activity 67 ;  but  it  should  be  remembered  that  blood 
serum  freed  of  diffusible  material  by  dialysis  may  also  show 
antipeptic  activities.68  0.  Schwarz,  working  in  Hofmeister 's 
laboratory,  found  after  heating  pepsin  solutions  to  above  60° 
C.  a  substance  capable  of  inhibiting  peptic  activity  which 
apparently  had  been  in  the  solutions  before  subjection  to 
heat  and  which  was  not  formed  directly  from  the  pepsin 
itself.69  Whether  any  of  these  contributions,  however,  have 
a  physiological  bearing  seems  decidedly  questionable. 

For  example,  knowing  that  pepsin  can  be  easily  separated 
from  a  solution  by  animal  charcoal  one  might  hesitate  to 

65  Literature  upon  the  protection  of  the  stomach  and  intestine  from  auto- 
digestion:  CI.  Fermi  (S'assari),  Centralbl.  f.  Bakteriol.,  56,  55,  1910,  and  Arch, 
di  farmacol.  sperim.,  10,  449,  1911;  cf.,  Centralb.  f.  d.  ges.  Biol.,  13,  No.  369, 
1912;    C.  Oppenheimer,  Fermente,  3d  ed.,  270-271,  1910. 

66  E.  Weinland  (Physiol.  Inst.,  Munich),  Zeitschr.  f.  Biol.,  U,  1,  45,  1902. 
"  L.  Blum  and  E.  Fuld,  Zeitschr.  f .  klin.  Med.,  58,  5-6,  1906. 

M  M.  Jacoby,  Biochem.  Zeitschr.,  2,  247,  1906. 

89 O.  Schwarz  (Physiol.  Chem.  Institut.,  Strassburg),  Hofmeister's  Beitr., 
6,  524,  1905. 


AUTODIGESTION  25 

think  that  the  prevention  of  the  action  of  a  gastric  juice  after 
addition  of  gastric  epithelial  cells  is  due  solely  to  "anti- 
pepsin."70 

The  following  experiment  by  E.  S.  May  in  the  laboratory 
of  Rene  du  Bois-Reyniond  71  is  instructive.  The  serosa  and 
mucosa  of  a  dog's  stomach  were  separately  prepared  and 
spread  out  over  glass  plates,  and  placed  in  gastric  juice. 
After  eighteen  hours  the  mucosa  was  not  changed ;  but  the 
serosa  was  markedly  acted  upon,  at  one  place  with  complete 
penetration. 

The  question  has  been  approached  from  another  stand- 
point, too,  by  introducing  living  tissue  into  the  opened 
stomach  of  an  animal.  Although  these  experiments  have 
not  been  productive  of  uniform  results  (a  living  spleen  with 
its  blood  vessels  attached  has  been  digested  quite  rapidly), 
we  must  accept  the  fact  that,  for  example,  the  foot  of  a  live 
frog  introduced  into  the  stomach  of  another  frog,  or  perhaps 
a  loop  of  living  intestine  placed  into  an  incised  stomach,  may 
remain  intact  for  many  hours.72  On  the  other  hand,  very 
active  solutions  of  trypsin  have  been  known  to  digest  living 
tissue  (tails  of  rats  and  mice).73 

In  conclusion  mention  may  be  made  of  such  observations 
as  those  of  Claudio  Fermi  showing  that  many  aquatic  ani- 
mals (protozoa,  worms,  crustaceans,  insects)  may  live  with- 
out the  least  harm  in  trypsin-solutions.74  A  solution 
of  trypsin,  capable  of  rapidly  digesting  a  large  lump  of 
coagulated  albumin,  has  been  found  to  be  without  any  effect 
upon  the  tiny  mass  of  protoplasm  of  an  infusorian,  unpro- 

10  R.  duBois-Reyniond,  Berl.  physiol.  Ges.,  July  21,  1911,  Centralbl.  f. 
Physiol.,  25,  774,  1911. 

T1 1.  c. 

"  Neumann,  Centralbl.  f .  allg.  Pathol.,  18,  1,  1907 ;  Kathe,  Berliner  klin. 
Wochenschr.,  1908,  2135;  Katzenstein,  ibid.,  1749;  G.  Hotz,  Mitt.  a.  d. 
Grenzgebieten  d.  Med.  u.  Chir.,  21,  143,  1909;    R.  du  Bois-Reymond,  1.  c. 

"L.  Kirchheim  (Labor.  M.  Cremer,  Cologne),  Arch.  f.  exper.  Pathol.,  26, 
352,  1911. 

71  CI.  Fermi,  1.  c. 


26  GASTRIC  DIGESTION  OF  PROTEINS 

tected  by  any  tegumentary  covering,  after  as  much  as  a 
month's  exposure.  The  Italian  author  just  mentioned  has 
concluded  therefore  that  the  living  cell  protects  itself  against 
the  digestive  enzymes  of  the  stomach,  intestine,  and  pan- 
creas, not  by  antienzymes,  nor  by  protective  coverings,  nor 
yet  by  any  special  sort  of  impermeability,  but  much  more 
likely  by  the  resistive  ability  of  the  whole  living  cell  itself. 
The  simple  reply  to  the  question  why  the  living  cell  is  not 
attacked  is  therefore  this:  "Because  it  is  alive."  With 
such  an  answer  the  problem  has  circled  back  to  exactly  the 
same  point  where  Hunter  started  one  hundred  and  forty 
years  ago.  It  is  to  be  hoped  that  perhaps  the  next  century 
and  a  half  will  really  accomplish  something  in  the  way  of 
progress. 

Origin  of  the  Round  Ulcer  of  the  Stomach. — In  a 
limited  way  the  question  as  to  the  mode  of  origin  of  the 
round  ulcer  of  the  stomach  is  related  with  that  of  gas- 
tric autodigestion.  Time  after  time  explanations  for  this 
lesion  have  proposed  some  local  circulatory  disturbance 
in  a  given  area  of  the  mucosa  (from  a  spasm  of  the  vessels, 
thrombosis  or  hemorrhage)  with  autolysis  of  the  portion 
involved.75  We  have  been  able  repeatedly,  too,  to  produce 
gastric  ulcers  experimentally  in  animals,  as  by  injection  of 
diphtheria  toxin,76  gastrotoxic  serum,77  by  feeding  bouillon 
cultures  of  bacterium  coli,78  by  repeated  serum  injections 79 
(as  one  of  the  features  of  anaphylaxis),  as  well  as  by  the 
poison  of  the  Gila  monster  (Heloderma  suspectum).80  The 
last  mentioned  experiments   (conducted  under  Leo  Loeb) 

75  Cf.  the  extensive  material  of  R.  Beneke,  Verb.  d.  Deutsche  pathol.  Ges., 
Kiel,  1908,  284. 

'"Rosenau  and  Anderson,  Journ.  Infect.  Diseases,  4,  1,  1907. 

77  M.  J.  Bolton,  Proc.  Roy.  Soc,  1905-06,  Series  B,  77 ;  1909,  Series  B,  79, 
cited  by  Rehfuss,  v.  infra. 

T.  B.  Turck,  Journ.  Amer.  Med.  Assoc,  1906,  1753,  cited  by  Rosenau  and 
Anderson,  v.  sup. 

79  Gay  and  Southard,  Journ.  of  Med.  Research,  190S,  cited  by  Rehfuss, 
v.  infra. 

80  M.  E.  Rehfuss,  University  of  Pennsylvania  Medical  Bulletin,  22,  105,  1909. 


CHYMOSIN  27 

suggest  that '  the  hemorrhages  in  the  mucosa  as  well  as 
thromboses  may  not  be  primary  lesions  in  the  production  of 
ulcers,  but  rather  secondary  to  and  produced  by  the 
ulceration. 

Chymosin. — A  short  review  of  the  problem  of  the  lab- 
coagulation  will  serve  to  conclude  the  present  lecture. 

It  may  be  confidently  asserted  that  the  question  of  the 
rennet-ferment  or  chymosin  is  the  oldest  physiological- 
chemical  problem  which  has  concerned  mankind.  For, 
many,  many  thousands  of  years  ago,  when  humanity  was  not 
interested  in  observation  of  nature  and  in  contemplations 
about  natural  philosophy,  the  nomadic  herdmen  were  well 
acquainted  with  the  use  of  the  gastric  mucous  membrane  in 
curdling  milk. 

A  mere  glance  over  the  extremely  extensive  literature 
dealing  with  the  lab  process  gives  one  the  impression  of  an 
impenetrable  thicket  of  apparently  diametrically  opposed 
observations  and  theories,  just  as  in  the  study  of  blood 
coagulation. 

Starting  with  the  observations  of  Hammersten  many 
attempts  have  been  made  to  outline  the  lab-process  as  a 
double-phased  one  in  which  the  bulk  of  the  casein  is  first 
changed  into  paracasein,  which  upon  the  addition  of  a  suf- 
ficient amount  of  calcium  salts  is  thrown  down  as  the  almost 
insoluble  calcium  paracaseinate  or  cheese,  a  small  part  of 
the  protein  remaining,  however,  in  solution  as  an  albumose- 
like  whey-albumin  from  a  coincident  splitting  process.  This 
simple  formulation  has  not  entirely  harmonized,  however, 
with  all  the  experimental  findings  of  a  large  group  of  investi- 
gators who  have  been  interested  in  the  subject,  relating  to 
ferment-kinetics,  the  physical-chemical  characteristics  of 
milk,  the  inhibition  and  stimulation  of  the  lab-process  by 
various  agents,  to  parachymosin  and  prochymosin,  the  part 
played  by  calcium  salts,  antiferments,  and  other  comparable 


28  GASTRIC  DIGESTION  OF  PROTEINS 

factors.81  The  many  contradictions  are  not  to  be  wondered 
at  when  we  remember  that  the  lab-coagulation  is  really  a 
complex  process.  Ivar  Bang  concludes  his  exhaustive  in- 
vestigations upon  the  subject  with  the  opinion  that  the 
calcium  salts  of  the  milk  are  distributed  among  the  organic 
and  inorganic  acids,  the  lactalbumin,  lactoglobulin  and 
casein;  that  the  casein  by  virtue  of  its  acid  nature  combines 
with  the  whole  group  of  milk  bases;  that  there  is  not  one 
paracasein  alone  but  that  there  are  formed,  long  before 
coagulation  is  apparent,  a  number  of  different  paracaseins 
with  variable  but  increasing  affinity  for  calcium  phosphate, 
and  that  at  a  certain  stage  these  compounds  separate  from 
solution  and  coagulation  takes  place.82 

Ultramicroscopic  Studies  of  Lab-process. — Kreidl  and 
Neumann83  have  been  able  to  explain  very  satisfactorily 
by  direct  ultramicroscopic  observation  a  number  of 
features  (especially  that  involved  in  the  differences  be- 
tween cow's  milk  and  human  milk)  which  have  more  than 
once  been  regarded  as  due  to  variation  in  the  degree  of  solu- 
tion of  the  casein  in  the  milk.  In  the  milk  of  different  species 
of  animals  there  arevisible  minute  bodies  (lactokonids),  pos- 
sibly identical  with  suspended  casein  or  caseinated  calcium. 
"It  has  been  shown  by  ultramicroscopic  study  of  milk  of 
various  animals  that  in  all  kinds  of  milk  except  human 
there  may  be  found  in  addition  to  the  fat  globules  great  num- 
bers of  a  second  corpuscular  element.     The  plasmatic  space 

81 M.  Arthus,  J.  Bang,  G.  Becker,  L.  Blum,  E.  Fuld,  M.  van  Herwerden, 
S.  G.  Hedin,  H.  Köttlitz,  S.  Löwenhart,  E.  Laqueur,  L.  Morgenroth,  L.  Pinkus- 
sohn,  E.  Petry,  C.  Pages,  H.  Reichel,  K.  Spiro,  W.  Sawjalow,  B.  Slowzoff, 
S.  Schmidt-Nielsen,  G.  Warneken,  J.  Wohlgemuth  and  many  others.  Literature 
upon  the  Lab-process  and  the  Proteins  of  Milk:  E.  Fuld,  Ergebn.  d.  Physiol., 
1,  408-504,  1902;  R.  W.  Raudnitz,  ibid.,  2,  193-251,  1903;  E.  Laqueur,  Biochem. 
Centralbl.,  4,  318,  1905;  F.  Samuely,  Handb.  d.  Biochem.,  1,  567-570,  1909; 
C.  Oppenheimer,  Fermente,  3d  ed.,  286-312,  1909;  A.  Schlossmann  and  S. 
Engel,  Handb.  d.  Biochem.,  3',  405-432,  1910. 

82 1.  Bang  (Lund),  Skandin.  Arch.  f.  Physiol.,  25,  105,  1911. 

83  A.  Kreidl  and  A.  Neumann  (Physiol.  Instit.,  Univ.  of  Vienna),  Sitzungs- 
bericht d.  Wiener  Akad.  Mathem-Naturwiss.,  kl.,  117'",  March,  1908;  cf.  also 
Centralbl.  f.  Physiol.,  22,  133,  1908,  Pfliiger's  Arch.,  128,  523,  1908. 


BACTERIAL  INVOLVEMENT  IN  LAB-PROCESS        29 

between  the  fat  globules  is  full  of  very  minute  particles  in 
active  molecular  movement,  often  in  such  great  numbers  that 
nothing  of  the  otherwise  dark  looking  plasma  is  to  be  seen, 
and  the  whole  field  of  vision  is  apparently  filled  by  a  dancing 
mass  in  which  the  fat  globules  lie  embedded.  .  .  .  Fresh 
human  milk  may  be  distinguished  from  this  picture  at  the 
first  glance.  In  the  human  milk  the  plasmatic  field  looks 
black.  .  .  .  If  a  preparation  be  made  of  a  milk  with  lab- 
ferment  added  it  will  be  seen  that  at  first  the  particles  collect 
into  minute  groups  recognizable  as  composed  of  the  lacto- 
konids ;  the  smaller  aggregates  then  unite  into  larger  ones, 
the  latter  entangling  the  fat  globules  and  finally  sinking  to 
the  bottom  of  the  container.  .  .  .  Coincidently  in  the 
tube  from  which  the  preparation  was  taken  coagulation  can 
be  grossly  seen." 

From  this  one  would  picture  the  lab  coagulation  as  a 
process  characterized  by  the  gradual  clumping  of  suspended 
colloidal  particles,  the  individual  phases  of  which  are  con- 
stantly intermingling  and  therefore  beyond  any  chance  of 
schematic  arrangement  in  chemistry.  Here,  just  as  in  case 
of  the  process  of  blood  coagulation,  one  cannot  but  feel  that 
too  much  importance  has  been  assigned  to  the  details  of  a 
separation  process  which  is  an  expression  of  disturbance  of 
equilibrium,  and  that  too  at  tremendous  expense  of  effort  and 
ingenuity.  An  architect  who  is  seeking  information  about 
the  collapse  of  a  building  is,  of  course,  particularly  anxious 
to  discover  the  cause  of  the  collapse.  But  he  would  scarcely 
waste  any  great  amount  of  energy  in  finding  out  in  detail 
whether  at  the  moment  of  the  fall  a  certain  gable  or  a  certain 
arch  had  given  way  a  little  earlier  or  later  or  a  little  to  one 
side  or  to  the  other. 

Bacterial  Involvement  in  Lab-process. — Recent  observa- 
tions have  been  made  by  Kreidl  and  Lenk 84  which  deserve 

"A.  Kreidl  and  E.  Lenk,  Biocliem.  Zeitschr.,  36,  357,  1911. 


30  GASTRIC  DIGESTION  OF  PROTEINS 

notice,  bearing  upon  the  participation  of  a  hitherto  neglected 
factor,  that  of  bacterial  infection,  in  the  process  of  lab- 
coagulation.  They  point  out  that  sterile  milk  will  not 
coagulate  in  sterile  vessels  if  treated  with  sterile  rennin; 
but  merely  touching  the  milk  with  the  non-sterile  finger  or 
the  addition  of  a  few  drops  of  ordinary  milk  will  cause 
curding. 

Much  thought  has  been  devoted  to  the  formulation  of  an 
acceptable  conception  of  the  physiological  purpose  of  the 
lab-process.  That  an  eventual  change  of  the  milk  intro- 
duced into  the  stomach  into  a  firm  curd,  so  that  this  can  pass 
into  the  intestine  only  bit  by  bit,  gradually,  thus  protecting 
the  intestine  against  being  flooded  with  food-proteins,  and 
that  this  in  many  animals  is  of  importance  in  the  nourish- 
ment of  the  young, — all  this  goes  without  question.  There 
is  reason  to  question,  however,  whether  the  greatest  value  of 
the  rennin,  which  is  found  widely  distributed  in  the  digestive 
organs  of  vertebrates,  many  invertebrates  and,  too,  in  the 
juices  of  many  plants,85  should  not  be  sought  for  in  an  alto- 
gether different  direction. 

Plastins. — Observations  of  A.  Danilewski  and  his  numer- 
ous students86  that  rennin  (and  also  extracts  of  intestine 
and  of  pancreas)  gives  rise  to  precipitation  in  solutions  of 
products  of  peptic  digestion  suggest  that  these  precipitates 
may  be  considered  as  an  expression  of  a  synthetic  fermenta- 
tion, possibly  directed  toward  the  regeneration  of  the  split 
protein.  But  the  attractive  prospect  that  in  plastins  we  are 
seeing  intermediate  products  of  a  fermentative  protein 
synthesis,  has  unfortunately  all  too  soon  met  the  fate  of  the 
most  of  the  brilliant  expectations  of  this  world. 

Question  of  the  Identity  of  Pepsin  and  Rennin. — Obser- 
vations   of    this    kind    (mainly    from    Pawlow    and    his 

85  W.  Biedermann,  Handb.  d.  vergleich.  Physiol.,  2',  1289,   1911. 

""Kurajeff,  Lawrow,  Lukomnik,  Nürnberg,  Okunew,  Salaskin,  Sawjalow, 
Schapirow  and  others.  Cf.  also  R.  0.  Herzog,  Zeitschr.  f.  physiol.  Chem.,  39, 
305,  1903;    H.  Bayer  (Hofmeister's  Laborat.),  Hofmeister's  Beitr.,  If,  554,  1903. 


INDENTITY  OF  PEPSIN  AND  RENNIN  31 

school)  have  developed  the  idea  that  pepsin  and  rennin  are 
fundamentally  identical ;  that  the  lab-action  is  nothing  else 
than  the  reversed  synthetizing  manifestation  of  the  same 
ferment  which  normally  behaves  as  a  peptic  protein  cleav- 
age-enzyme. This  view  undoubtedly  is  an  attractive  one, 
and  meets  our  demand  for  simplification  of  our  concepts  of 
complicated  natural  phenomena.  The  great  interest  mani- 
fested in  this  view  is  probably  explicable  on  this  basis.  An 
unusually  large  number  of  comprehensive  researches  have 
been  devoted  within  recent  years  to  this  question  of  the 
identity  of  pepsin  and  lab-ferment.  Pawlow's  many  associ- 
ates 87  are  constantly  directing  attention  to  the  distinct 
parallelism  between  the  action  of  pepsin  and  lab.  They 
have  been  unable  to  separate  the  two  ferments  either  by  dif- 
fusion,88 filtration 89  or  by  electric  conduction.90  Hammer- 
sten  and  very  many  other  authors,91  on  the  other  hand,  have 
unquestionably  produced  in  different  ways  solutions  of 
pepsin  which  no  longer  coagulate  milk,  and,  too,  lab  solutions 
which  no  longer  manifest  any  peptic  ability.  An  American 
writer 92  has  demonstrated  that  on  passing  an  electric  cur- 
rent under  certain  conditions  through  a  fluid  containing  both 
rennin  and  pepsin  the  latter  will  be  completely  destroyed 
while  the  lab  remains  unchanged.     The  physiologist  Duc- 

wCf.  J.  W.  A.  Gewin  (Physiol.  Instit.,  Utrecht.),  Zeitschr.  f.  physiol. 
Chem.,  54,  32,  1907;  W.  Sawitsch,  ibid.,  55,  84,  1908;  W.  van  Dam,  ibid.,  64, 
316,  1910;  Th.  J.  Migay  and  W.  Sawitsch,  ibid.,  63,  405,  1909;  W.  Sawitsch, 
ibid.,  68,  13,  1910. 

88  R.  O.  Herzog  (Karlsruhe),  Zeitschr.  f.  physiol.  Chem.,  60,  306,  1909. 

M  C.  Funk  and  A.  Niemann,  Zeitschr.  f.  physiol.  Chem.,  68,  263,  1910. 

90  C.  A.  Pekelharing  and  W.  E.  Ringer,  Zeitschr.  f.  physiol.  Chem.,  7.5, 
282,  1911. 

91  O.  Hammersten,  Zeitschr.  f.  physiol.  Chem.,  56,  18,  1908;  68,  119,  1910; 
74,  142,  1911;  S.  Schmidt-Nielsen  ( Hammersten's  Laboratory),  ibid.,  68,  92, 
1906;  A.  Rakoczy,  ibid.,  68,  421,  1910;  J.  F.  B.  van  Hasselt,  ibid.,  10,  171, 
1910;  A.  E.  Porter,  Journ.  of  Physiol.,  42,  389,  1911;  L.  Blum  and  W.  Böhme, 
Hofmeister's  Beitr.,  9,  74,  1906;  A.  E.  Taylor,  Journ.  of  Biol.  Chem.,  5,  399, 
1909:    A.  Rakoczy  (Kiew),  Zeitschr.  f.  physiol.  Chem.,  68,  421,  1910. 

92  W.  E.  Bürge  (Johns  Hopkins  Univ.),  Amer.  Journ.  of  Physiol.,  29, 
330,  1912. 


32  GASTRIC  DIGESTION  OF  PROTEINS 

ceschi,93  working  in  Argentina,  has  shown  that  pepsin  but 
not  chymosin  is  to  be  found  in  the  stomach  of  certain  mar- 
supials (Didelphis) .  In  view  of  positive  evidence  like  this, 
indicating  the  duality  of  pepsin  and  rennin,  the  frequent 
failure  to  establish  such  differentiation  cannot,  in  the  opinion 
of  the  author,  be  held  as  contradictory ;  positive  results  are 
of  more  significance,  it  seems  to  the  author,  than  negative 
ones  in  such  a  matter.  Identity  between  pepsin  and  rennin 
for  the  present  at  least  certainly  does  not  seem  to  be  proved. 
As  for  the  frequently  expressed  suggestion  that  the  two 
ferments  may  not  be  precisely  identical  but  different ' '  sides ' ' 
of  one  single  ferment,  slightly  different  sidechains  of  one 
" giant  enzyme  molecule,"  the  author  confesses  his  complete 
ignorance,  not  knowing  how  to  proceed  in  attempting  to 
make  an  exact  differentiation  between  different  enzymes  and 
" different  sidechains  of  some  one  ferment."  To  use  the 
expression  of  a  distinguished  jurist,  the  author  is  not  enough 
of  an  expert  in  this  matter  to  see  even  darkly. 

83 V.  Ducceschi  (Cordova),  Arch,  di  Fisiol.,  5,  413,  1908. 


CHAPTER  II 
THE  PROTEOLYTIC  PANCREATIC  FERMENT 

Transfer  of  the  Food  from  the  Stomach  into  the  Intes- 
tine.— The  previous  chapter  having  been  devoted  to  the 
process  of  protein  digestion  in  the  stomach,  the  subject  of  the 
method  of  transfer  of  the  food  from  the  stomach  into  the 
intestine  may  with  propriety  be  next  considered. 

This  process  has  been  approached  experimentally  in  a 
variety  of  ways,  as  by  the  production  of  gastric  and  duo- 
denal fistulas,  by  rontgenoscopy  of  the  stomach  after  intro- 
ducing bismuth  nitrate  into  the  food  ingested,  by  tube 
analysis  of  the  gastric  contents,  etc.  Hofmeister  and  Schütz 
studied  by  direct  observation  the  movements  of  a  living 
exsected  stomach  kept  in  a  moist  chamber ;  P.  v.  Grützner 
examined  frozen  sections  of  stomachs  of  animals  killed  in 
different  stages  of  digestion ;  Scheunert  followed  the  move- 
ments and  partition  of  the  gastric  contents  by  the  special 
means  of  administering  colored  food,  etc.  Although  it  is  im- 
possible to  go  at  length  into  the  subject  the  attention  of  the 
reader  should  be  directed  at  least  to  the  importance  of  chem- 
ical regulation  of  the  reflex  pylorus  closure  from  the  intes- 
tine; our  knowledge  of  which  is  mainly  due  to  the  recent 
studies  of  Pawlow,  Moritz,  Cannon,  London,  Cohnheim,  Tob- 
ler  and  others.1  We  know  from  observation  that  a  dog  with 
a  duodenal  fistula  discharges  the  water  through  the  fistula 

1  Literature  upon  the  Passage  of  the  Food  from  the  Stomach  into  the 
Intestine:  0.  Cohnheim,  Nagel's  Handb.  d.  Physiol.,  2,  560-568,  1907;  Physiol, 
d.  Verd.  u.  Ernähr.,  pp.  13-26,  1908;  E.  S.  London,  Handb.  d.  Biochem.,  8"  68- 
73,  1909;  0.  Cohnheim  and  F.  Marchand,  Zeitschr.  f.  Physiol.  Chem.,  63,  41, 
1909;  F.  Best  and  0.  Cohnheim,  ibid.,  69,  113,  1910;  Sitzungsber.  d.  Heidelber- 
ger Akadamie,  1910;  W.  B.  Cannon  (Harvard  Medical  School),  Amer.  Jour,  of 
Physiol.,  20,  283,  1900;  cf.  also  F.  Meyer  (Kissingen),  Zeitschr.  f.  physiol. 
Chem.,  11,  466,  1911;  M.  Kirschner  and  E.  Mangold  (Greifswald),  Mitteil.  a. 
d.  Grenzgebieten  d.  Medizin  u.  Chir.,  23,  446,  1911;  R.  Kaufmann  and  R. 
Kienböck,  Med.  Klinik,  1911,  1150. 

3  33 


34  PROTEOLYTIC  PANCREATIC  FERMENT 

about  as  it  is  drunk,  quite  naturally  suggesting  comparison 
with  Baron  Münchhausen's  well  known  horse,  with  all  its 
drinking  merely  pouring  out  the  water  from  the  cut  which 
has  severed  away  the  posterior  half  of  its  body.  But  if, 
instead  of  water,  acid  gastric  contents  come  in  contact  with 
the  duodenal  mucous  membrane,  there  at  once  occurs  a  reflex 
closure  of  the  pylorus.  In  this  way  the  intestine  is  protected 
from  further  flooding  with  acid  gastric  material.  At  the 
same  time  entrance  of  alkaline  digestive  fluids  (the  bile, 
pancreatic  juice  and  intestinal  juice)  into  the  duodenum  is 
brought  about  by  the  acid  material,  these  juices  neutralizing 
the  acid.  As  soon  as  the  pylorus  opens  again  another  charge 
of  acid  is  expelled  into  the  duodenum ;  and  the  same  perform- 
ance automatically  repeats  itself.  According  to  Cannon 
reflex  relaxation  is  induced,  directly  by  contact  of  the  acid 
chyme  upon  the  pars  pylorica.  Besides  the  influence  of 
acid  from  the  intestine,  closure  of  the  plorus  may  be 
caused  by  fat;  and  according  to  the  studies  of  0.  Cohn- 
heim  and  his  associates  it  is  not  a  matter  of  consequence 
where  the  oil  or  acid  is  placed  in  the  small  intestine.  From 
the  fact  that  cocainizing  the  intestine  prevents  the  contrac- 
tion the  reflex  nature  of  the  act  cannot  be  in  doubt.  There 
are,  too,  in  all  probability  a  number  of  other  factors  involved 
in  the  regular  discharge  of  the  gastric  contents  besides  the 
hydrochloric  acid  and  the  fat  of  the  chyme,  especially  the 
consistence  of  the  food. 

Passage  of  the  Intestinal  Contents  into  the  Stomach. — In 
contrast,  a  matter  of  physiological  interest,  first  brought  to 
attention  within  the  past  few  years,  is  that  of  the  entrance  of 
intestinal  contents  into  the  stomach,  observed  by  Pawlow  and 
Boldyreff.  After  the  introduction  of  fatty  foods  particu- 
larly, but  sometimes  also  after  fasting,  and,  too,  when  there  is 
an  especially  high  degree  of  gastric  acidity,  it  may  happen 
that  a  mixture  of  intestinal  secretion,  pancreatic  juice  and 
bile  regurgitates  into  the  stomach  to  such  an  extent  that  the 
hydrochloric  acid  of  the  stomach  may  be  neutralized  and 


PANCREATIC  FISTULAS  35 

peptic  digestion  interfered  with.  Abderhalden  and  his  as- 
sociates have  shown  that  the  splitting  of  a  dipeptid,  glycyl- 
1-tyrosin,  which  is  not  produced  normally  in  the  stomach,  can 
in  these  cases  be  detected  in  the  gastric  juice  by  polarimetry 
(after  neutralizing  the  acidity  of  the  gastric  juice  by  sodium 
bicarbonate).  It  has  been  proposed  to  base  a  method  for 
obtaining  the  human  pancreatic  juice  for  diagnostic  pur- 
poses upon  this  fact.  In  application  an  "oil  test-break- 
fast," consisting  of  about  200  ccm.  of  olive  oil,  containing 
free  oleic  acid,  is  introduced  by  a  stomach-tube  after  neu- 
tralization of  the  gastric  acidity  by  alkali.  The  gastric  con- 
tent withdrawn  after  a  half  hour  is  readily  freed  from  the 
oil  and  often  is  found  stained  greenish  by  bile  and  may  show 
the  presence  of  trypsin.  Whether  the  method,  for  which 
great  expectations  were  entertained,  will  prove  of  actual 
value  in  diagnosis  must  for  the  present  be  held  in  judgment.2 
Pancreatic  Fistulas. — As  is  well  known,  the  chyme  having 
passed  into  the  intestine  becomes  mixed  with  the  secretion  of 
the  pancreatic  gland,  to  the  secretory  process  of  which  organ 
attention  should  next  be  called.  Although  Claude  Bernard 
had  introduced  canulas  into  the  excretory  duct  of  the  pan- 
creas and  had  endeavored  to  thus  study  the  method  of  secre- 
tion of  this  important  organ,  for  a  long  time  progress  was  not 
satisfactory,  simply  because  there  was  too  great  a  departure 
from  the  normal  physiological  conditions  arising  from  the 
severity  of  the  operative  procedure.  Very  often  after  such  a 
' '  temporary"  fistula  has  been  made,  even  if  the  experimental 
animal  be  in  the  height  of  digestion,  but  little  or  no  secre- 
tion can  be  obtained.  Here  again  the  incomparable 
Eussian  physiologist,  Pawlow,3  was  the  first  to  overcome 

2  Literature  upon  the  Passage  of  Pancreatic  Juice  and  Intestinal  Fluid  into 
the  Stomach :  Important  monographs  by  W.  Boldyreff,  Ergebn.  d.  Physiol.,  11, 
127-213,  1911;  cf.  also  W.  Boldyreff,  Pflüger's  Arch.,  121,  13,  1908;  E.  Abder- 
halden and  F.  Medigreceanu,  Zeitschr.  f.  physiol.  Chem.,  57,  317,  1908;  E. 
Abderhalden  and  Schittenhelm,  ibid.,  59,  230,  1909;  J.  Lewinski  (Minkowski's 
Clinic,  Greifswald),  Deutsche  med.  Wochenschr.,  1908,  1582. 

3  Literature  upon  Production  of  Pancreatic  Fistulas :  J.  Pawlow,  Ergebo, 
d.  Physiol.,  1,  266-272,  1902;    Nagel's  Handb.  d.  Physiol.,  2,  728-742,  1907. 


36  PROTEOLYTIC  PANCREATIC  FERMENT 

the  special  technical  difficulties.  He  proceeded  to  bring  a 
patch  of  the  duodenal  wall  surrounding  the  orifice  of  the 
excretory  duct  to  the  skin  surface  and  stitched  it  into  the 
cutaneous  margins  of  the  wound.  In  this  way  he  obtained  a 
permanent  fistula  and  the  advantage  of  continuous  observa- 
tion of  the  glandular  activity  at  his  convenience.  Even 
with  this  advance  in  technique  the  results  obtained  were  not 
thoroughly  satisfactory  because  of  the  activation  of  the 
secretory  fluid  obtained  from  the  fistula  by  the  enterokinase 
(v.  infra.)  of  the  mucous  membrane  surrounding  it.  Only 
by  careful  removal  of  this  mucous  membrane  which  had 
been  healed  into  the  cutaneous  wound  and  by  isolating  the 
orifice  of  the  duct  by  stitching  it  to  the  margins  of  the  wound 
can  there  be  obtained  sufficient  approach  to  physiological 
conditions  to  insure  that  really  normal  pancreatic  fluid  will 
be  obtained. 

Such  conditions  being  established  it  is  possible  to  de- 
termine the  influences  by  which  the  pancreas  is  normally 
stimulated.  Undoubtedly  the  most  important  factor  in  this 
connection  is  the  entrance  of  the  acid  content  of  the  stomach 
into  the  duodenum.  The  hydrochloric  acid  is,  it  is  safe 
to  say,  the  most  effective  stimulant  to  pancreatic  secretion ; 
the  influence  of  the  fatty  substances  of  the  food  is  apparently 
more  or  less  questionable 4 ;  but  a  psychic  agency  must  in  all 
likelihood  be  recognized.  As  to  the  method  by  which  the 
secretion  of  the  gland  is  set  in  operation,  doubtless  both 
nervous  and  chemical  mechanism  must  be  held  possible. 

Secretin. — Bayliss  and  Starling  were  able  to  demonstrate 
that  the  introduction  of  acid  into  an  intestinal  loop  will 
maintain  the  pancreas  in  activity  even  after  section  of  both 
vagi  and  the  splanchnic  nerves,  and  after  extirpation  of  the 
solar  plexus.  After  exclusion  of  all  nervous  communication 
between  the  intestinal  loop  and  the  rest  of  the  body  the  flow 
of  pancreatic  juice  is  quite  as  free  as  if  the  nerves  were  in- 

*0.  Cohnheim  and  Ph.  Klee,  Zeitschr.  f.  physiol.  Chem.,  78,  464,   1912. 
(Soaps  apparently  have  more  influence  than  do  the  neutral  oils.) 


SECRETIN  37 

tact.  From  this  fact  the  authors  named  conclude  "it  was 
clear  that  the  message  from  the  isolated  loop  was  carried  by 
way  of  the  blood  to  the  pancreas  and  that  it  must  be  some 
new  type  of  chemical  substance  which  originated  in  the 
intestinal  mucous  membrane  under  the  influence  of  the  acid. 
In  confirmation  of  this  conclusion  the  mucous  membrane  of 
the  upper  portion  of  the  small  intestine  may  be  scraped  off, 
mixed  with  0.4  per  cent.  HCl  and  the  mixture  filtered,  when 
it  will  be  found  that  injection  of  this  filtrate  directly  into  the 
circulation  will  induce  a  special  flow  of  pancreatic  fluid.  To 
this  new  substance  produced  under  the  influence  of  acid  in 
the  intestinal  cells  we  have  applied  the  name  'secretin.'  "5 

The  work  of  the  authors  quoted  has  been  amply  confirmed 
in  many  quarters;  and  the  chain  of  proof  has  been  in  a 
sense  completed  by  Wertheimer's  discovery  of  secretin 
in  the  blood  of  an  isolated  intestinal  loop  into  which  acid  had 
been  introduced.  The  well  considered  and  masterly  studies 
of  Bayliss  and  Starling  should  be  regarded  as  truly  classical. 
In  this  connection  Swale  Vincent6  in  a  critical  review  of  the 
whole  question  of  internal  secretion  regards  the  action  of 
secretin  (after  the  glycogenetic  function  of  the  liver)  as  the 
best-attested  example  of  an  "internal  secretion"  and  in 
strict  sense  more  definitely  established  than  the  internal 
secretions  of  the  thyroid  gland  and  the  adrenal.  And  yet 
the  conditions  of  pancreatic  secretion  remain  so  confused 
that  the  question  of  the  role  and  significance  of  secretin  is 
in  the  author's  opinion  still  far  from  final  solution. 

In  the  first  place  it  should  be  remembered  that,  as  shown 
by  Wertheimer  and  Fleig,  the  flow  of  pancreatic  secretion 
may  be  induced  by  the  introduction  of  acid  into  an  intestinal 
loop  even  if  the  blood  of  the  loop  is  completely  cut  out  from 

8  Literature  upon  Secretin :  W.  M.  Bayliss  and  E.  H.  Starling,  Ergebn.  d. 
Physiol.,  5,  670-676,  1906;  E.  H.  Starling,  Lectures  on  Recent  Advances  in 
the  Physiology  of  Digestion,  London,  1906;  J.  Pawlow,  Nagel's  Handb.  d. 
Physiol.,  2,  734-742,  1907;  S.  Rosenberg,  ibid.,  8',  141-146,  1910;  C.  Oppen- 
heimer,  Fermente,  3d  ed.,  193-194,  1910. 

"Swale  Vincent,  Ergebn.  d.  Physiol.,  9,  496-500,  1910. 


38  PROTEOLYTIC  PANCREATIC  FERMENT 

the  general  circulation  and  fails  to  pass  to  the  pancreas.  A 
number  of  authors,  especially  those  of  the  Pawlow  school, 
are  disposed  to  assume  that  the  pancreatic  secretion  is  gov- 
erned by  a  dual  mechanism,  partly  nervous  and  partly 
humoral.7 

Secretin  seems  to  be  a  thermostabile  substance,  soluble 
in  alcohol,  not  specific  for  any  particular  kind  of  animal,  but 
apparently  identical  in  all  vertebrates.  The  belief  that  it  is 
formed  from  a  "prosecretin"  when  acid  comes  in  contact 
with  the  intestinal  mucosa  is  improbable,  as  it  can  be 
shown 8  that  solutions  having  secretin-like  influence  may  be 
obtained  by  treating  the  mucous  membrane  of  the  intestine 
with  sodium  chloride  solution,  soaps,  alcohol,  peptone, 
chloral  hydrate  or  even  with  hot  water ;  the  usual  employ- 
ment of  mineral  acids  is  readily  explicable  from  the  fact  that 
such  an  agent  prevents  the  destruction  or  masking  of  the 
secretin  action  by  other  agents  contained  in  the  extracts  of 
intestinal  mucous  membrane.  Fleig's  assumption  of  the 
necessity  of  recognizing  different  kinds  of  secretin  ("sapo- 
krinin,"  "ethylokrinin,"  etc.),  according  to  the  method  of 
derivation,  is  probably  not  justified.9 

Secretin  and  Cholin  and  the  Vasodilations. — From  an 
investigation  which  the  author's  friend,  Carl  Schwarz,10 
and  the  author  conducted,  it  was  found  that  cholin  exists 
in  the  secretin  prepared  according  to  the  method  of 
Bayliss  and  Starling.  The  influence  of  such  an  extract 
is   unquestionably   to   be   partly   attributed   to    this   base, 

7  Cf .  A.  Bylina  (Institut,  exp.  Med.,  St.  Petersburg),  Pfliiger's  Arch.,  142, 
531,  1911. 

8  Delezennes,  and  Pozerski,  Fleig,  Camus,  Falloise,  Gley  and  others. 

*  While  C.  Delezennes  and  E.  Pozerski,  Journ.  de  Physiol.,  1%,  521,  540,  1912, 
in  their  most  recent  publications  insist  upon  the  non-existence  of  a  "  pro- 
secretin," W.  Stepp  (Univ.  College,  London:  Journ.  of  Physiol.,  43,  441,  1912) 
holds  that  secretin  practically  always  is  to  be  found  in  the  intestinal  mucous 
membrane  as  prosecretin,  free  secretin  being  found  only  occasionally  in  small 
quantities;  cf.  also  S.  Lalou,  Journ.  de  Physiol.,  Uh  241,  465,  530,  1912;  E. 
Gley,  ibid.,  507. 

10  0.  v.  Fürth  and  C.  Schwarz,  Pfliiger's  Arch.,  12^,  427,  1908;  cf.  Litera- 
ture thereto  appended. 


SECRETIN  AND  CHOLIN  39 

the  physiological  influence  and  significance  of  which  have 
elsewhere  (Vol.  I  of  this  series,  Chemistry  of  the  Tissues, 
pp.  185-190)  been  detailed.  Secretin  cannot,  however,  be 
identified  as  cholin,  the  activities  of  the  two  sub- 
stances being  in  no  wise  parallel ;  the  secretory  effect  of  cholin 
(but  not  of  secretin)  being  completely  eliminated  by  atropin. 
"Secretin"  is,  however,  apparently  not  a  simple  substance, 
but  is  perhaps  a  mixture  of  a  number  of  agents  capable  of 
exciting  secretory  activity,  in  the  group  of  which  cholin 
doubtless  is  included.  Keeping  in  mind  the  fact  that  cholin 
is  an  exceedingly  labile  substance,  subject  to  marked  changes 
from  comparatively  simple  disturbances  (as  seen,  for  in- 
stance, in  its  transformation  into  neurin,  muscarin  and 
acetylcholin)  and  to  functional  exaggerations  (cf.  Vol.  I,  p. 
189,  of  this  series,  The  Chemistry  of  the  Tissues),  it  is 
not  easy  to  get  rid  of  the  idea  that  perhaps  secretin  is  nothing 
more  than  a  mixture  of  cholin  and  of  its  transformation 
products.  Of  course  this  is  no  more  than  an  unproved  con- 
jecture, which  it  is  true  would  serve  to  bring  secretin  and 
the  "vasodilatins"  (probably  closely  related  to  cholin) 
under  a  common  heading. 

As  previously  indicated,  cholin  is  one  of  the  general 
tissue  constituents ;  and  from  the  investigations  of  Popiel- 
ski  n  and  his  students  "  vasodilatins' '  can  doubtless  be  ex- 
tracted from  practically  all  tissues.  These  are  powerful 
substances  capable,  when  injected  intravenously  with  proper 
precautions,  of  inducing  fall  of  blood-pressure,  secretion  of 
saliva,  of  gastric,  intestinal  and  pancreatic  fluids,  increase  of 
peristalsis,  spasms,  loss  of  haemic  coagulability  and  in- 
creased flow  of  the  lymph.  Popielski  believes  that  a  relative 
anaemia,  dependent  upon  the  lowered  blood-pressure,  and 
consecutive  irritation  of  the  nervous  centres  are  fundamen- 

11  L.  Popielski  (Lemberg),  Centralbl.  f.  Physiol.,  16,  505,  1902;  19,  801, 
1906;  Pflüger's  Arch.,  120,  451,  1907;  121,  239,  1908;  126,  483,  1909;  128, 
191,  223,  1909. 


dO      PROTEOLYTIC  PANCREATIC  FERMENT 

tal  to  the  symptom-complex ;  he  does  not  accept  the  physio- 
logical importance  of  secretin  for  normal  production  of  the 
pancreatic  secretion,  and,  while  willingly  acknowledging  the 
existence  of  a  nervous  mechanism  as  operative  in  the 
process,  does  not  recognize  a  humoral  factor.  However,  it 
must  be  insisted  upon  that,  from  the  studies  of  Bayliss  and 
Starling,  the  substance  in  intestinal  extracts  which  depresses 
the  blood  pressure  is  not  identical  with  secretin,  and  that 
secretin-containing  solutions  can  be  prepared  which  are 
apparently  free  from  the  former.  It  must  be  acknowledged 
that  a  clear  insight  into  the  matter  has  by  no  means  been 
attained. 

The  attendant  difficulties  may  be  the  more  readily  appre- 
hended if  it  is  recalled  that  the  nervous  mechanism  con- 
cerned in  the  pancreatic  secretory  process  is  a  complex  one 
and  is  really  very  little  understood.  We  know  that  the  pan- 
creas receives  its  nervous  impulses  both  from  the  vagus  and 
the  splanchnic ;  both  nerves  furnish  fibres  to  the  blood  ves- 
sels of  the  gland,  and  from  stimulation  of  either  according  to 
circumstances  there  may  be  induced  either  increase  or  in- 
hibition of  the  secretion.  C.  Schwarz12  was  able  to  show 
that  cholin  can  influence  the  pancreatic  secretion  in  one  way 
or  the  other  according  to  the  quantity  injected,  on  the  one 
hand  inhibiting  the  flow  through  its  excitation  of  the  vagus 
centre,  on  the  other  inducing  activity  by  stimulation  of 
peripheral  autonomous  secretory  nerves.  It  may  therefore 
be  appreciated  without  further  discussion  that  it  is  difficult 
if  not  impossible  to  come  to  a  satisfactory  conclusion  as  to 
the  identity  or  differentiation  of  any  of  the  active  con- 
stituents of  organic  extracts  from  simple  comparison  of 
their  influences  upon  the  pancreatic  secretion  and  from  other 
physiological  factors.  Until  we  are  able  to  deal  with  chem- 
ically definite  substances,  it  is  to  be  feared  we  will  be  unable 
to  escape  from  such  contradictions. 

12 C.  Schwarz  (Vienna),  Centralbl.  f.  Physiol.,  23,  337,  1909. 


ENTEROKINASE  41 

Mention  should  be  made  also  of  the  fact  that  acid  exhibi- 
tion is  capable  of  stimulating  reflexly  the  pancreatic  secre- 
tion not  only  from  the  duodenum  but  also,  as  discovered  by 
Popielski,13  and  by  London  and  C.  Schwarz,14  from  a  large 
part  of  the  small  intestine.  London  and  Schwarz  determined 
the  fact  that  besides  the  duodenum,  the  whole  of  the  jejunum 
and  the  upper  portion  of  the  ileum,  but  not  the  middle  part  of 
the  ileum,  manifest  this  ability,  which  therefore  resides  in 
about  two-thirds  of  the  entire  length  of  the  intestine. 

Besides  secretin  and  cholin,  pilocarpin  is  capable  of 
stimulating  the  secretory  activity  of  the  pancreas  if  intro- 
duced into  the  blood;  albumoses  and  other  similar  sub- 
stances may  act  in  the  same  way.15 

Enterohinase. — Passing  to  consideration  of  the  pancre- 
atic secretion  itself,  Pawlow  is  to  be  credited  with  the  impor- 
tant discovery  that  trypsin  is  not  secreted  in  a  completed 
form.  The  secretion  as  it  passes  out  of  the  duct  of  the  gland 
contains  rather  a  trypsin-zymogen,  which  is  activated  by  con- 
tact with  an  agent  arising  from  the  intestinal  mucosa,  entero- 
hinase, and  is  transformed  thereby  into  true  trypsin.  This 
puzzling  agent,  which  is  also  doubtless  of  importance  in  acti- 
vating the  human  pancreatic  secretion,16  has  been  the  object 
of  intensive  study  for  the  past  few  years.  A  group  of  eminent 
French  authors 17  and  a  number  of  other  investigators 18  have 
endeavored  to  determine  the  real  nature  of  enterokinase ;  but 
opinions  arrived  at  are  at  wide  variance.19  The  belief  that 
the  substance  is  a  ferment  has  met  with  considerable  oppo- 

13  L.  Popielski,  Zeitschr.  f.  physiol.  Chem.,  11,  186,  1911. 

14  E.  S.  London  and  C.  Schwarz,  Zeitschr.  f.  physiol.  Chem.,  68,  346,  1910. 

15  E.  Gley,  Journ.  de  Physiol.,  Uh  507,  1912. 

18  Observations  of  A.  Ellinger,  M.  Kohn,  K.  Glässner  and  J.  Wohlgemuth. 
17  Dastre,  Camus,  Delezennes,  Frouin,  Gley  and  associates. 

18Bayliss  and  Starling,  O.  Cohnheim,  Ciaccio,  C.  Foä,  Hamburger  and 
Hekma,  Vernon,  E.  Zunz. 

19  Literature  upon  Enterokinase:  Th.  Brugsch,  Handb.  d.  Biochem.,  3',  115- 
116,  1910;  S.  Rosenberg,  ibid.,  3',  127-136,  1910;  C.  Oppenheimer,  Fermente, 
3d  ed.,  208-215,  1910;  W.  Biedermann,  Winterstein's  Handb.  d.  vergleich. 
Physiol.,  2',  1409-1415,  1911. 


42  PROTEOLYTIC  PANCREATIC  FERMENT 

sition.  A  number  of  authors  would  relate  the  adsorptive 
readiness  of  enterokinase  (as  in  its  ready  fixation  by 
fibrin)  with  its  action,  and  believe  that,  in  the  same  way  as 
in  haemolysis  complement  is  fixed  to  a  red  blood  cell  by  the 
intermediation  of  an  amboceptor,  trypsinogen  is  fixed  to  the 
protein  molecule  as  complement  by  the  binding  power  of 
enterokinase  (as  amboceptor) .  Enterokinase  is  a  thermola- 
bile  substance;  but  0.  Cohnheim's  observation  that  it  is 
soluble  in  90  per  cent,  alcohol  is  clearly  not  in  harmony  with 
the  idea  that  it  is  of  the  nature  of  an  enzyme.  It  is  scarcely 
believed  any  longer  that  enterokinase  is  derived  from 
leucocytes ;  it  is  apparently  directly  produced  from  the  cells 
of  the  intestinal  mucous  membrane,  although  there  seems  to 
be  some  active  material  of  similar  character  also  present  in 
leucocytes  at  times. 

Activation  of  Trypsinogen  by  Calcium  Salts  and  Similar 
Substances. — Besides  enterokinase  a  considerable  group  of 
other  agents  is  known  to  be  capable  of  activating  trypsino- 
gen. Calcium  salts  particularly  have  been  the  object  of  care- 
ful investigation  by  Delezenne  in  their  marked  relations  with 
trypsinogen.  Activation  of  an  inactive  dyalized  pancreatic 
juice,  after  the  latter,  mixed  with  a  salt  of  calcium,  has  been 
kept  in  an  incubator  for  a  number  of  hours,  may  result  sud- 
denly, as  if  explosively ;  if  paraffined  tubes  have  been  used 
activation  by  calcium  salts  may  be  postponed  for  some 
days.20 

With  special  precautions  activation  of  trypsinogen  may 
be  induced  by  quite  a  variety  of  colloids  (as  by  toluidin  blue) . 
It  is  therefore  scarcely  remarkable  that  the  expressed  juices 
from  various  organs,  milk  and  similar  substances,  have  been 
found  capable  of  inducing  the  same  result.  Even  bacteria 
can  convert  trypsinogen  into  trypsin ;  the  author  has  in  an 
earlier  volume  (cf.  Vol.  I  of  this  series,  Chemistry  of  the 

20  Cf .  also  J.  Wohlgemuth  ( Experimental  Division  of  the  Pathol.  Institut., 
Berlin),  Observations  upon  Human  Pancreatic  Fluid,  Biochem.  Zeitschr.,  39, 
302,  1912. 


INDIVIDUALITY  OF  TRYPSIN  43 

Tissues,  p.  501)  discussed  their  probable  relation  with  the 
genesis  of  the  once  celebrated  freighting -theory  (in  accord- 
ance with  which  the  pancreas  was  freighted  with  digestive 
ferment  from  the  spleen). 

Even  trypsin  itself  seems  to  belong  to  the  group  of  acti- 
vators of  trypsinogen ;  at  any  rate  when  the  least  amount  of 
trypsin  is  introduced  into  an  inactive  solution  of  the  ferment 
it  is  spontaneously  activated. 

Individuality  of  Trypsin. — Question  has  arisen  whether 
the  digestive  pancreatic  ferment  is  chemically  one  single  sub- 
stance. L.  Pollack  has  asserted  that  besides  the  trypsin 
there  is  a  mucin  digesting  ferment,  "glutinase,"  in  the  pan- 
creatic juice  ;  Vernon  has  accepted  the  existence  of  a  peptone- 
splitting  ferment  {"pancreatic  erepsin").  Other  investiga- 
tions rather  favor  the  idea  of  the  individuality  of  the  protein- 
digestive  ferment  of  the  pancreas.  For  example,  the  expla- 
nation of  the  observed  fact  that  trypsin,  first  acidulated  with 
hydrochloric  acid  and  then  neutralized,  will  freely  digest 
gelatin  but  no  other  proteins  is  to  be  found  in  the  fact  that  in 
highly  alkaline  conditions  it  digests  all  proteins  but  on  addi- 
tion of  acid  digests  only  gelatine;  if,  thereafter,  alkali  be 
added  the  normal  digestive  properties  recur.21  In  a  recent 
study  K.  Glässner  and  A.  Stauber  have  again  asserted  the 
existence  of  an  erepsin  in  the  pancreatic  fluid  along  with 
trypsin.22 

Doubtless  the  activity  of  trypsin  is  influenced  very 
largely  by  the  ions  present  in  the  solution.  A  dialysed  solu- 
tion of  trypsin,  for  instance,  shows  diminished  activity ;  but 

21 H.  M.  Vernon,  Jour,  of  Physiol.,  30,  330,  1903;  K.  Mays  (Laboratory 
of  A.  Kossel),  Zeitschr.  f.  physiol.  Chem.,  38,  502,  1903;  Jt9,  124,  188,  1906; 
W.  M.  Bayliss  and  E.  H.  Starling,  Journ.  of  Physiol.,  30,  61,  1903;  L.  Pollack, 
Hofmeister's  Beitr.,  6,  95,  1905;  Arch.  f.  Verdauungskr.,  11,  362,  1905;  M. 
Ehrenreich,  Arch.  f.  Verdauungskr.,  11,  261,  364,  1905;  A.  Ascoli  and  B. 
Neppi,  Zeitschr.  f.  physiol.  Chem.,  56,  135,  1908;  G.  Schaeffer  and  E.  F. 
Terroine,  Journ.  de  Physiol.,  12,  884,  906,  1910. 

n  K.  Glässner  and  A.  Stauber  ( E.  Freund's  Lab. ) ,  Biochem.  Zeitschr.,  25, 
204,  1910. 


44      PROTEOLYTIC  PANCREATIC  FERMENT 

it  is  interesting  to  note  the  return  of  its  efficiency  as  soon 
as  the  normal  salts  of  pancreatic  fluid  are  added.23  Only 
the  briefest  comment  can  here  be  made  upon  the  extensive 
literature  dealing  with  the  influence  of  variations  of  alkalin- 
ity, temperature,  neutral  salts,  poisons  of  various  kinds, 
*  *  antif  erments ' '  and  adsorbing  media  upon  the  activity  of 
trypsin;  the  author  must  refer  for  fuller  details  of  these 
subjects  to  Carl  Oppenheimer 's  valuable  work  on  ferments.24 

Conversion  of  Trypsin  into  Zymoid. — The  observations 
of  Bayliss  are  presumably  of  general  interest  as  they  may 
perhaps  bring  us  a  step  nearer  to  comprehension  of  the 
mystery  of  ferment  activities.  By  determination  of  con- 
ductivity Bayliss  discovered  that  trypsin  inactivated  by 
standing  does  not  lose  its  power  of  fixation  of  protein. 
He  compares  the  inactivation  of  trypsin  to  Ehrlich 's 
conception  of  the  change  of  a  toxine  into  a  toxoid.  In 
the  transformation  of  trypsin  into  a  "zymoid"  he  sup- 
poses it  loses  its  ergophore  group,  still  retaining,  however, 
its  haptophore  group,  which  serves  to  fix  it  to  a  protein 
molecule.  There  has  been  no  lack  of  experiments  with  other 
ferments  to  apply  to  the  enzyme  problem  the  conceptions 
which  have  come  in  spite  of  all  opposition  to  dominate  our 
theories  as  to  immunity.  We  may  think  as  we  will  of  these 
modes  of  thought ;  the  heuristic  value  of  these  and  of  similar 
schematic  ideas  cannot  be  controverted.  Their  justification 
can  be  maintained,  however,  only  until  something  better  can 
be  substituted.25 

Action  of  Trypsin  Upon  Polypeptids. — Undoubted  prog- 
ress has  been  accomplished  by  the  systematic  researches  of 
Emil  Fischer,  Abderhalden  and  Bergell  in  determining  the 

23  A.  Frouin  and  A.  Compton,  Compt.  rend.,  153,  1032,  1911. 

M  C.  Oppenheimer,  Fermente,  3d  ed.,  pp.  185-202,  1909 ;  cf.  also  S.  G.  Hedin, 
Biochem.  Journ.,  1,  474,  484,  1906;  2,  81,  1907;  L.  Michaelis  and  H.  Davidsohn, 
Biochem.  Journ.,  86,  280,  1910. 

20  W.  M.  Bayliss,  Arch.  Sciences  biol.,  St.  Petersburg,  11,  supplement  261, 
cited  by  O.  Cohnheim,  Nagel's  Handb.  d.  Physiol.,  2,  582,  1907. 


ADAPTATION  OF  PANCREATIC  SECRETION  45 

field  of  tryptic  action  upon  definite  proteins,  particularly  in 
relation  to  chemically  pure  Polypeptids ;  the  situation  is  com- 
parable to  one  in  which  of  two  unknowns  in  an  equation,  if 
one  may  somehow  be  eliminated,  the  theoretical  possibility  of 
a  solution  attained  is  probable.  What  are  the  structural 
peculiarities  upon  which  the  possibility  of  a  given  polypeptid 
being  acted  upon  by  trypsin  depends?  "The  (molecular) 
structure  of  the  individual  compounds  comes  into  considera- 
tion at  once, ' '  says  Abderhalden.26  ' '  An  instructive  example 
is  found  in  the  relation  of  alanyl-glycin  (CH3.CH(NH2).CO. 
NH.CH2.C00H)  and  its  isomer  glycyl-alanin  (NH2.CH2. 
CO.NH.CH  ( CH3 )  .COOH) .  The  former  is  split,  the  latter  is 
not.  The  particular  kind  of  amino  acid  is  also  of  importance. 
In  the  dipeptids,  for  example,  hydrolysis  is  favored  if  alanin 
acts  as  acyl.  The  resistance  of  dipeptids  containing 
a-aminobutyric  acid,  a-aminovalerianic  acid  and  leucin  as 
acyl  is  very  notable.  The  number  of  aminoacids  concerned 
in  the  structure  of  a  polypeptid  is  also  of  importance.  The 
glycin  group  illustrates  this  nicely.  Gylcyl-glycin,  diglycyl- 
glycin  and  triglycyl-glycin  are  not  split;  while  hydrolysis 
takes  place  in  case  of  tetraglycyl-glycin. "  It  is  of  special 
interest,  however,  that  pancreatic  fluid  splits  only  those  Poly- 
peptids in  whose  molecular  structure  the  natural  optically- 
active  aminoacids  take  part;  and  that  the  economy,  if 
raceme  bodies  are  at  its  disposition,  may  often  be  able  to 
utilize  only  one  of  the  two  optically  opposite  components. 
This  is  true  both  for  the  mammalian  body  and  for  the  low- 
est forms  of  plants  (cf.  Vol.  I  of  this  series,  Chemistry  of  the 
Tissues,  p.  15). 

Adaptation  of  Pancreatic  Secretion  to  the  Food. — The 
Pawlow  school  has  assumed  a  general  adaptability  of  the 
secretion  of  the  pancreas  to  the  particular  type  of  food 
which  may  obtain  at  any  given  time;  in  other  words,  that 

ME.  Abderhalden,  Lehrb.  d.  phyaiol.  Chem.,  2d  ed.,  626-628,  1909;  cf. 
Literature,  thereto  appended. 


46      PROTEOLYTIC  PANCREATIC  FERMENT 

the  pancreas  adapts  itself  to  its  work  in,  as  it  were,  an 
intelligent  manner,  by  increasing  its  proteolytic  ferment  for 
meat,  its  amylolytic  ferment  for  a  meal  of  bread,  or  its 
lactose  ferment  for  milk.  This  view,  however,  cannot  with- 
stand criticism ;  it  bespeaks  an  effort  to  realize  a  harmonious 
principle  pervading  the  arrangements  of  nature  which  goes 
somewhat  too  far  afield.27 

Quantitative  Determination  and  Ferment  Law  of  Tryp- 
sin.— The  realization  that  there  are  a  number  of  physiological 
questions  related  with  trypsin  which  rest  upon  the  possibility 
of  its  quantitative  determination,  has,  as  in  case  of  pepsin 
and  by  employment  of  similar  principles,  led  to  numerous 
attempts  to  accomplish  this.  Thus  Metts'  tubes  of  albumin 
or  gelatin  have  been  used.28  Trypsin  has  been  allowed  to  act 
upon  dissolved  casein,  after  Vollhard's  method,29  and  from 
the  increase  of  acidity  of  the  resulting  albumoses  the  degree 
of  digestion  has  been  determined  by  titration.  Gross 30  dis- 
solves casein  in  soda  solutions  (as  in  E.  Fuld's  method), 
arranges  a  series  of  tubes  with  increasing  amounts  of 
trypsin,  and  observes  after  a  time  whether  acidulation  with 
acetic  acid  continues  to  give  rise  to  turbidity.  Jacoby 31  ob- 
serves the  degree  of  clearing  of  deposits  of  ricin  or  edestin ; 
V.  Henri 32  and  Bayliss 33  follow  the  progress  of  digestion 
physico-chemically  by  determining  the  conductivity,  and 
Brailsford  Robertson 34  by  determining  the  refraction  index 
of  a  soda-casein-solution  after  precipitation  of  undigested 
casein  by  acetic  acid.    A  simple  and  apparently  very  precise 

27  Literature  upon  Adaptation  of  Pancreatic  Secretion  to  Food :    S.  Rosen- 
berg, Handb.  d.  Biochem.,  3',  138-140,  1910. 

28  P.  Hattori,  Arch,  internat.  de  Pharm.,  IS,  255,  1909. 

20  W.  Löhlein,  Hofmeister's  Beitr.,  7,  120,  1905;    Faubel,  ibid.,  10,  35,  1907. 
30  O.  Gross,  Arch.  f.  exper.  Pathol.,  58,  157,  1908. 

81  M.  Jacoby,  Biochem.  Zeitschr.,  10,  299,  1908. 

82  V.  Henri,  and  Larguier  des  Bancels,  C.  R.  Soc.  de  Biol.,  55,  563,  787,  866; 
Jahresber.  f.  Tierchem.,  33,  512-514,  1903. 

85  W.  M.  Bayliss,  1.  c. 

84  T.  Brailsford  Robertson,  Journ.  of  Biol.  Chem.,  12,  23,  1912. 


PARENTERALLY  INTRODUCED  TRYPSIN  47 

method  has  been  devised  by  P.  v.  Grützner 35  on  the  principle 
of  his  method  of  estimating  pepsin.  Fibrin  is  stained  with 
Spiritblau  (diphenylrosanilin)  and  the  color  given  to  the 
digestive  fluid  when  the  fibrin  is  digested  in  a  0.1  per  cent, 
soda  solution  is  determined  colorometrically. 

While  the  Schütz-Borissow  rule  may  be  found  applicable 
within  certain  limits  for  the  digestion  of  solid  proteins,  there 
seems  to  exist  for  dissolved  proteins  a  simple  ratio  between 
the  quantity  of  ferment  and  quantity  of  protein  dissolved 
by  it.  "Both  groups,"  thinks  Palladin,36  "are  correct, 
those  who  believe  that  the  Schütz-Borissow  rule  obtains  for 
trypsin  and  those  who  think  that  Vollhard's  rule  of  direct 
ratio  applies.  It  is  not  of  consequence  which  method  is  used. 
Probably  the  truth  is  that  one  ferment  molecule  does  exactly 
as  much  work  as  any  other,  that  n  molecules  will  do  n 
times  as  much  as  one  in  case  no  accidental  inhibition  occurs 
and  the  ferment  molecules  can  have  full  access  to  their  prey 
(if  the  term  be  permitted),  that  is  to  the  protein,  which  is  all 
that  Grützner  proved  for  pepsin  originally. ' ' 

Toxicity  of  Parenterally  Introduced  Trypsin. — Refer- 
ence may  here  be  made  to  a  matter  of  general  physiological 
interest,  the  toxicity  which  parenterally  introduced 
trypsin  or  pancreatic  tissue  manifests  upon  the  body. 
In  spite  of  the  resistance  of  living  tissues  to  digestive  fer- 
ments, mentioned  in  the  preceding  lecture,  there  unquestion- 
ably is  a  decided  production  of  necrosis  when  trypsin  is  in- 
jected subcutaneously.  "When  the  pancreas  of  a  dog  under- 
goes necrosis  death  quickly  ensues,  and  that  whether  the 
pancreas  was  that  belonging  to  the  animal  or  a  foreign  gland 
transplanted  under  aseptic  precaution.  It  is  very  interest- 
ing, as  discovered  by  Achalme,  that  animals  may  be  im- 
munized to  a  high  degree  against  this  toxic  influence  by 

30  A.   Palladin    (Physiol.   Institut.,   Tübingen),   Pflüger's  Arch.,   134,   337, 
1910;    W.  Waldschmidt,  ibid.,  143,  189,  1911. 
30  P.  Palladin,  1.  c,  p.  364. 


48  PROTEOLYTIC  PANCREATIC  FERMENT 

previous  gradual  treatment  with  trypsin.  G.  v.  Bergmann 
has  been  able  to  induce  in  dogs  such  a  high  grade  of 
immunity  that  the  animals  were  able  to  bear  the  implantation 
of  an  entire  foreign  pancreas,  a  procedure  which  in  unpre- 
pared animals  is  followed  by  death  within  twenty  hours  at 
most.37 

It  may  be  conjectured  that  the  toxic  effect  of  the  parenter- 
ally  introduced  trypsin  depends  upon  a  sudden  hydrolytic 
cleavage  of  the  proteins  in  the  living  body  produced  in  the 
same  way  as  trypsin  in  vitro  dissociates  proteids.  To  de- 
termine this  point  experimentally  the  author  with  his  col- 
league, Carl  Schwarz,38  has  studied  the  effect  of  intra- 
peritoneal injections  of  emulsions  of  pancreas  introduced 
under  aseptic  precautions.  Although  acute  toxic  symptoms 
were  produced  in  the  experiment  animals,  the  latter  could 
be  protected  by  previous  treatment  with  increasing  dosage 
of  trypsin,  and  rendered  resistant  to  comparatively  large 
amounts  of  the  pancreatic  material.  By  careful  metabolic 
studies  the  investigators  were  able  to  prove  that  intra- 
peritoneal injections  of  large  amounts  of  trypsin  or  pan- 
creatic tissue  disturbs  the  nitrogen  balance  so  that  for  one 
or  two  weeks  the  nitrogen  excretion  is  irregular  (a  series 
of  irregular  increases  and  decreases).  The  total  nitrogen 
output  was,  however,  not  altered,  as  might  have  been  ex- 
pected if  an  exaggerated  protein  destruction  and  important 
catabolism  of  the  tissue  proteids  had  taken  place.  It  is  by 
no  means  safe  to  conclude  that  the  marked  toxicity  of  par- 
enterally  introduced  trypsin  is  to  be  referred  to  a  direct 
influence  upon  protein-metabolism.  According  to  Fischler, 
animals  which  have  been  previously  treated  with  trypsin 

37  P.  Achalme,  Ann.  de  l'lnstit.  Pasteur.,  15,  737,  1901 ;  G.  v.  Bergmann, 
Zeitschr.  f.  exper.  Pathol.,  3,  400,  1906;  G.  Dorberauer,  Beitr.  z.  klin.  Chir., 
48,  456,  1906;  N.  Gulecke,  Arch.  f.  klin.  Chir.,  85,  644,  1908;  G.  v.  Bergmann  and 
N.  Gulecke,  Münchener  med.  Wochenschr.,  57,  1673,  1910;  D.  Kirchheim 
(Cologne),  Verh.  d.  Kongr.  f.  innere  Med.,  21 1  595,  1910. 

88  O.  v.  Fürth  and  C.  Schwarz,  Biochem.  Zeitschr.,  20,  384,  1909. 


PARENTERALLY  INTRODUCED  TRYPSIN     49 

react  to  very  small  amounts  of  phosphorus  or  hydrazin  by 
suffering  marked  fatty  degeneration  of  the  liver.39 

The  question  of  "antitrypsin"  in  the  serum  has  been 
elsewhere  discussed,  and  the  author  prefers  not  to  return 
to  this  rather  uninteresting  subject.  In  what  manner 
trypsin  normally  gains  access  to  the  blood  circulation  cannot 
easily  be  determined  with  certainty;  especially  when  the 
body  is  flooded  with  the  enzyme  it  has  been  recognized  in  the 
urine.40  When  it  is  remembered  how  little  we  know  of  the 
changes  many  chemically  well-defined  substances  undergo  in 
the  animal  body,  it  does  not  seem  at  all  remarkable  that  the 
fate  of  so  indefinite  a  substance  as  trypsin  remains  unknown. 

39  Fischler  and  Wolff,  29.  Kongr.  f.  innere  Med.,  19,  IV,  1912. 
*°K.    Bamberg    (II   Med.    Clin.,    F.    Kraus,    Berlin),    Zeitschr.   f.    exper. 
Pathol.,  5,  7¥L,  1909;    E.  Graf  von  Schönborn,  Zeitschr.  f.  Biol.,  53,  386,  1910. 


CHAPTER  III 

PROTEIN-DIGESTION  IN  THE  INTESTINE 

Erepsin. — In  the  preceding  chapters  we  have  dealt  in 
some  detail  with  pepsin  and  trypsin.  Our  attention  is  now 
turned  to  a  third  ferment  directly  involved  in  protein-diges- 
tion, the  erepsin  of  the  intestinal  secretion,  the  discovery  of 
which  is  due  to  the  acuteness  of  observation  of  Otto 
Cohnheim. 

Erepsin  is  an  enzyme  which  does  not  act  upon  most  of 
the  native  albumins,  but  reduces  albumoses  and  peptones  to 
crystallizable  products.  "In  connection  with  the  action  of 
erepsin  upon  the  individual  intermediate  substances  between 
albumin  and  the  amino  acids, "  Cohnheim  observes,  "it 
should  be  said  that  peptones,  that  is  peptones  corresponding 
to  Kühne 's  conception,  lose  the  ability  to  respond  to  the 
biuret-reaction  very  quickly,  within  minutes  or  hours,  when 
in  contact  with  erepsin-solutions,  very  much  more  rapidly 
than  I  have  ever  observed  when  they  are  brought  in  contact 
with  active  pancreatic  extract.  Erepsin  acts  much  more 
slowly  upon  the  various  albumoses,  weeks  elapsing  before  the 
disappearance  of  the  biuret-reaction,  which  is  in  fact  a  rather 
deceptive  phenomenon.  Kutscher,  Seemann  and  Weinland, 
who  have  worked  with  erepsin  only  upon  albumin  and  who 
because  of  the  slowness  of  the  loss  of  biuret-reaction  have 
denied  any  real  importance  to  erepsin  in  digestion,  are  con- 
tradicted by  these  differences. ' '  The  influence  of  erepsin  is, 
however,  not  limited  to  the  protein  derivatives  of  higher 
molecular  composition.  Polypeptids  are  also  split,  as 
shown  by  the  investigations  of  Abderhalden  and  his  associ- 
ates and  the  studies  of  H.  Euler.  Thus  the  albumoses  and 
peptones  formed  from  ingested  proteins  by  the  action  of 

50 


EREPSIN  51 

pepsin  and  trypsin  fall  very  quickly  as  prey  to  erepsin  and 
are  broken  down  into  their  final  crystallizable  dissociation- 
products.1 

At  first  0.  Cohnheim's  brilliant  discovery  was  questioned 
by  many,  but  later  was  so  fully  confirmed  2  that  its  correct- 
ness cannot  logically  be  doubted.  Erepsin  is  neither  iden- 
tical with  trypsin  nor  does  it  come  from  the  pancreas.  Even 
where  the  pancreatic  secretion  cannot  gain  access  to  the 
intestine,  as  in  case  of  a  Thiry  fistula 3  or  after  ligation  of 
the  pancreatic  ducts,4  a  rich  supply  of  erepsin  is  found  in 
the  intestine  and  its  association  with  pepsin  under  these 
circumstances  accounts  for  the  continued  albumin  dis- 
sociation in  the  intestine.5 

If,  however,  the  pancreas  be  completely  extirpated  or 
atrophied,  general  metabolic  disturbances  ensue  of  so 
marked  a  type  that  there  can  be  no  wonder  that  protein 
digestion  should  eventually  suffer.  It  is  a  misconception 
to  class  erepsin  among  the  autolytic  tissue  ferments. 
Some  such  erepsin-like  influence  may  be  met,  according 
to  Vernon,  in  many  different  tissues,  which  will  be  con- 
sidered in  the  following  lecture;  this  is  really  a 
phenomenon  due  entirely  to  endocellular  enzymes,  whereas 
erepsin  undoubtedly  belongs  in  the  intestinal  secretion. 
It  is,  however,  not  a  matter  of  much  consequence  about  the 
name,  if  the  facts  of  its  capability  are  kept  clearly  in  mind. 

1  Literature  upon  Erepsin :  0.  Cohnheim,  Nagel's  Handb.  d.  Physiol.,  2, 
583-585,  1907;  Physiol,  d.  Verd.  u.  Ernährung,  Berlin  and  Vienna,  1908,  p. 
217;  F.  Samuely,  Handb.  d.  Biochem.,  1,  555,  1909;  Th.  Brugsch,  ibid.,  3',  112- 
115,  1910;   C.  Oppenheimer,  Fermente,  3d  ed.,  181-184,  1909. 

^Kutscher  and  Seemann,  S.  S.  Salaskin,  A.  Falloise,  J.  H.  Hamburger  and 
E.  Hekma,  L.  Tobler,  M.  Nagajama,  Lambert,  C.  Foä,  L.  Weekers,  E.  Rau- 
bitschek,  L.  Langstein  and  Soldin,  G.  Amantea  and  others. 

3  L.  Weekers,  Arch,  intern,  de  Physiol.,  2,  49 ;  cited  Centralbl.  f.  Physiol., 
19,  90,  1905. 

♦Th.  Brugsch,  Zeitschr.  f.  exper.  Pathol.,  6,  326,  1909;  K.  Glässner  and 
A.  Stauber  (E.  Freund's  Lab.),  Biochem.  Zeitschr.,  25,  204,  1910;  E.  Zunz 
and  L.  Mayer,  Bull.  Acad.  de  M£d.  de  Belgique  (4),  19,  509;  Jahresber.  f. 
Tierchem.,  35,  491,  1905. 

"Literature:    O.  Prym,  Handb.  d.  Biochem.,  3",  106-107  (1909). 


52  PROTEIN  DIGESTION  IN  THE  INTESTINE 

There  can  be  no  objection  to  regarding  erepsin  in  the  light  of 
a  "heterolytic"  ferment,  however,  even  if  it  be  not  an 
"autolytic"  one. 

From  snch  considerations  it  is  evident  that  nature  has 
fully  provided  means  to  insure  the  splitting  of  the  proteid 
constituents  of  the  food  into  their  end-products.  We  are  in 
position,  therefore,  to  proceed  a  step  further  and  take  up  the 
question  whether  there  is  any  evidence  that  the  provision  can 
be  traced  as  actually  operative  in  normal  digestion  in  further 
measure.6 

Extent  of  Protein  Dissociation  in  the  Intestine. — The 
classical  investigation  by  Carl  Ludwig  and  Salvioli  should 
be  recalled  showing  that  peptone  solution  may  disappear 
from  the  lumen  of  a  loop  of  the  small  intestine  (artificially 
perfused  with  blood)  without  peptone  becoming  demon- 
strable in  the  blood  used  in  perfusion.  Later,  in  1881,  Franz 
Hofmeister,  whose  pupil  the  author  was,  demonstrated  the 
disappearance  of  peptone  when  brought  in  contact  with 
gastric  mucosa  in  extracorporeal  conditions ;  and  N.  Neu- 
meister  made  a  similar  demonstration  for  the  intestinal 
mucosa.  The  interpretation  of  these  fundamental  and 
amply  corroborated  observations  suggesting  a  resorption 
process,  at  a  later  date  was  modified  by  the  discovery, 
mainly  due  to  work  by  Kutscher  and  Seemann,  Cohnheim, 
Cathcart  and  Leathes,7  that,  while  albumoses  and  peptones 
disappear  when  brought  in  contact  outside  the  body  with 
intestinal  mucosa,  this  is  due  not  to  their  resorption  but  to 
their  dissociation  into  more  simple  protein  derivatives. 

Moreover,  the  investigations  of  these  authors,  and  chiefly 


6  Literature  upon  the  Extent  of  Protein  Dissociation  in  the  Intestine: 
J.  Munk,  Ergebn.  d.  Physiol.,  1,  310-317,  1902;  O.  Cohnheim,  Nagel's  Handb.  d. 
Physiol.,  2,  629,  1907;  H.  Lüthje,  Ergebn.  d.  Physiol.,  7,  800-804,  1908;  O. 
Prym,  Handb.  d.  Biochem.,  3",  102,  1909;  W.  Biedermann,  Winterstein's 
Handb.  d.  vergl.  Physiol.,  2",  1448-1449,  1911. 

1  F.  Kutscher  and  J.  Seemann,  Zeitschr.  f.  physiol.  Chem.,  3>t,  528,  1902 ; 
35,  432,  1902;  49,  298,  1907;  O.  Cohnheim,  ibid.,  33,  451,  1901;  36,  13,  1902; 
1,9,  64,  1906;  51,  415,  1907;  E.  P.  Cathcart  and  J.  B.  Leathes,  Journ.  of 
Physiol.,  S3,  462,  1905. 


PROTEIN  DISSOCIATION  IN  THE  INTESTINE         53 

numerous  studies  prosecuted  by  Abderhalden,  London  and 
their  associates,8  left  no  doubt  as  to  the  constant  presence 
of  considerable  amounts  of  aminoacids  in  the  contents  of  the 
intestine  (even  if  dissociation  is  apparently  not  complete), 
and  too  of  notable  quantities  of  polypeptoids.9  The  intes- 
tinal contents  differ  decidedly  in  this  from  the  gastric  con- 
tent, which,  as  a  rule,  shows  no  aminoacids  at  all  or  at  most 
only  traces.  (In  the  instances  in  which  these  substances  do 
occur  in  the  stomach,  as  in  the  omasum  of  ruminants,  the 
possibility  of  the  existence  of  ferments  in  the  food  itself  must 
be  considered,10  as  it  has  been  indicated  from  the  work 
of  the  Ellenberger  Institute  that  under  certain  circumstances 
autolytic  ferments  may  relieve  the  animal  intestine  in  part 
of  its  work  of  digestion  and  may  act  as  substitutes  for  the 
body  enzymes.)  X1 

The  later  advances  in  the  chemistry  of  proteins,  espe- 
cially Emil  Fischer's  ester  method,  formol-titration  of 
aminoacids,  etc.,  harmonize  with  these  studies.  The  ester 
method  cannot  be  applied  to  the  determination  of  amino- 
acids in  the  intestinal  content  unless  special  provisions  (as 
refrigeration  during  the  estering  process,  etc.)  are  em- 
ployed, as  in  the  process  of  estering  it  is  possible  that 
aminoacids  may  be  split  off  from  proteid  substances.12 

It  is  impossible  to  deny  that  proteid  substances  are  separ- 
ated into  their  final  derivatives ;  but  it  is  another  question 
whether  resorption  normally  occurs  only  after  such  ad- 
vanced dissociation.  Three  possibilities  must  be  taken  into 
consideration.     In  the  first  place  absorption  of  an  impor- 

8  Baumann,  Funk,  Kautzsch,  v.  Körösy,  Medigreceanu,  Oppler,  Reemlin. 
Literature:    0.  Prym,  1.  c. 

9E.  Aberhalden,  Zeitschr.  f.  physiol.  Chem.,  74,  436,  1911. 

10  E.  Abderhalden,  W.  Klingemann  and  Th.  Pappenhusen,  Zeitschr.  f. 
physiol.  Chem.,  71,  411,  1911. 

11 W.  Grimmer  ( Ellenberger's  Lab.),  Biochem.  Zeitschr.,  !{,  SO,  1907;  cf. 
Literature,  there  appended. 

13  B.  O.  Pribram  (Vienna),  Zeitschr.  f.  physiol.  Chem.,  71,  472,  1911;  72, 
504.  1911. 


54  PROTEIN  DIGESTION  IN  THE  INTESTINE 

tant  part  of  the  protein  dissociation-derivatives  as  under- 
stood in  the  older  conceptions  may  take  place  in  the  stage 
of  "albumoses"  and  "peptones."  If,  however,  this  be  not 
the  case,  and  if  the  dissociation  proceeds  to  the  extent  of 
producing  crystallizable  products,  two  further  possibilities 
present  themselves:  either  these  crystallizable  derivatives 
are  absorbed  as  such,  or  they  undergo  a  synthetic  change, 
before  entering  the  blood,  into  high-molecular  protein 
derivatives  in  the  intestinal  wall. 

Passage  of  True  Proteins  and  High-molecular  Protein- 
derivatives  into  the  Blood. — In  considering  the  first  of  these 
possibilities  it  must  be  granted  that  under  certain  circum- 
stances high-molecular  protein  dissociation-products  and, 
too,  true  proteins,  can  pass  from  the  bowel  into  the  blood.13 
The  precipitin  reaction  and  anaphylactic  methods  assure  us 
of  the  possibility  of  determining,  with  precision  hitherto  un- 
dreamed of,  the  most  minute  quantities  of  foreign  proteins  in 
the  blood.14  We  know  today  that  it  is  possible  under  given 
conditions  to  determine  by  such  methods  proteid  substances 
absorbed  from  the  bowel,  as,  for  example,  after  flooding  the 
intestine  with  uncooked  eggs,  raw  milk  or  blood-serum.  The 
normal  protective  influence  of  the  intestinal  epithelium  is  ap- 
parently undeveloped  in  the  newly-born;  and,  too,  may  be 
decidedly  impaired  by  pathological  processes.15  It  may  be 
shown  experimentally  in  vitro, too, that  foreign  serum, toxins, 
hemolysins,  ferments  and  antiferments  of  various  kinds 
diffuse  more  rapidly  through  an  inflamed  intestinal  wall 
than  through  the  normal  wall  of  the  bowel;   this  perhaps 


J*  Literature  upon  Absorption  of  True  Proteins  and  High  Molecular 
Protein  Dissociation-products  from  the  Bowel:  O.  Cohnheim,  Nagel's  Handb. 
d.  Pbysiol.,  2,  624,  1907;  H.  Lüthje,  Ergebn.  d.  Physiol.,  7,  830-835,  1908; 
C.  Oppenheimer  and  L.  Pincussohn,  Handb.  d.  Biochem.,  i ',  705,  1911;  P.  Nolf, 
Journ.  de  Physiol.,  Nov.,  1907. 

14  F.  Micheli  (Turin),  Giorn.  Accad.  Med.  Torino,  73,  205,  1910. 

15Ganghofner  and  J.  Langer  (Prague),  Münchener  med.  Wochenschr.,  51, 
1497,  1904. 


PASSAGE  OF  TRUE  PROTEINS  55 

being  related  to  a  variation  in  the  degree  of  swelling.16 
Where  there  coexists  with  the  increased  permeability  of  the 
intestinal  wall  a  diminished  retention  by  the  urinary  filter, 
passage  of  the  foreign  protein  into  the  urine  can  be  de- 
tected,17 although  this  does  not  require  special  renal 
permeability  as  it  has  long  been  known  that  after  sub- 
cutaneous injection  of  albumoses,  albumin  and  similar  sub- 
stances these  substances  may  at  times  pass  directly  into  the 
urine.18  It  goes  without  saying  that  such  facts  are  not  only 
of  physiological  interest  but  are  also  of  importance  in 
medical  practice.  For  instance,  repeated  rectal  administra- 
tion of  egg  albumin  may  under  certain  circumstances  induce 
in  experiment  animals  a  fatal  marasmic  condition  with 
anaphylactic  phenomena.19  The  well-known  attempts  of 
Behring  to  introduce  anti-bodies  of  various  kinds  into  chil- 
dren in  milk  is  in  direct  relation  with  the  question  in  hand. 
A  full  discussion  of  the  subject  can  be  found  in  a  study  made 
by  UfFenheimer  in  the  laboratory  of  Max  Gruber.20 

Borchhardt  has  been  able  after  feeding  to  recover  in  the 
blood  two  proteids,  recognizable  in  minute  amounts  because 
of  their  characteristic  chemical  peculiarities,  hemielastin 
and  Bence-Jones  albumin  (v.  Vol.  I,  of  this  work,  The 
Chemistry  of  the  Tissues,  p.  511  ).21  And  yet  Abderhalden 
has  failed  to  find  elastin  in  the  blood,  tissues  or  in  the  urine 
after  administration  of  large  quantities.22 

18  E.  Mayerhofer  and  E.  Przibram  (R.  Paltauf'3  Instit.,  Vienna),  Zeitschr. 
f.  exper.  Pathol.,  7,  247,  1909;  Biochem.  Zeitschr.,  2k,  453,  1910;  M.  Loeper 
and  Ch.  Esmonet,  C.  R.  Soc.  de  Biol.,  6>t,  445,  1908. 

"  R.  Hecke  (M.  Gruber's  Labor.,  Munich),  Münchener  med.  Wochenschr., 
56,   1875,   1909. 

UH.  de  Waele  and  A.  J.  J.  Vandevelde  (Ghent),  Biochem.  Zeitachr.,  SO, 
227,  1910. 

»  L.  Petit  and  J.  Minet,  C.  R.  Soc.  de  Biol.,  6k,  22,  1908. 

-"A.  Uffenheimer,  Arch.  f.  Hygiene,  55,  140,  1905. 

21  L.  Borchhardt,  Zeitschr.  f.  physiol.  Chem.,  51,  506,  1907;  57,  3C5,  1908; 
L.  Borchhardt  and  H.  Lippmann  (Med.  Clinic,  Königsberg) ,  Biochem.  Zeitschr., 
25,  6,  1910. 

21 E.  Abderhalden  and  Rüehl,  Zeitschr.  f.  physiol.  Chem.,  69,  301,  1910. 


56  PROTEIN  DIGESTION  IN  THE  INTESTINE 

The  numerous  positive  findings  23  of  albumoses  in  the 
blood  of  animals  during  digestion  are  contradicted  by  a 
series  of  other  studies  in  which  the  higher  molecular  prod- 
ucts of  protein  dissociation  were  entirely  missed  in  the 
blood  at  the  height  of  digestion.24  A  recent  controversy  be- 
tween E.  Abderhalden  and  E.  Freund  in  reference  to  this 
discrepancy  brings  out  distinctly  the  difficulties  involved 
both  in  method  and  in  the  significance  of  the  results  of  ex- 
perimentation.25 It  is  extremely  difficult  to  coagulate  fully 
the  entire  mass  of  hsemic  proteins;  and  small  protein 
residua  which  have  escaped  coagulation  may  very  easily 
come  to  be  looked  upon  as  "albumoses."  Then,  too,  as  dis- 
cussed in  the  previous  volume  of  these  lectures  (Chemistry 
of  the  Tissues,  p.  246),  the  possibility  exists  that  non- 
coagulable  proteid  substances  ("serornucoid,"  etc.)  may  be 
formed  in  the  blood  itself.  And  besides,  autolytic  ferments 
exist  throughout  the  body,  and  where  small  amounts  of 
albumose-like  products  are  found  in  the  blood  they  may  as 
well  have  come  from  autolysis  of  the  hsemic  proteins  as  from 
the  intestine  as  resorbed  products  of  digestion.  And  finally 
it  may  be  very  properly  maintained  that,  even  if  small  quan- 
tities of  digestion  albumoses  are  positively  detected,  this 
does  not  contradict  the  proposition  that  the  bulk  of  the 
products  of  digestion  is  resorbed  only  after  complete 
dissociation. 

23  G.  Embden  and  F.  Knopp,  Hofmeister's  Beiträge,  3,  120,  1903;  L.  Lang- 
stein,  ibid.,  3,  373,  1903;  G.  v.  Bergmann  and  L.  Längstem,  ibid.,  6,  27,  1905; 
F.  Kraus  (E.  Freund's  Labor.),  Zeitschr.  f.  exper.  Patbol.,  S,  52,  1906;  E. 
Freund,  ibid.,  4,  3,  1907;  O.  Scbumm,  ibid.,  4,  453,  1904;  Erben,  Zeitschr. 
f.  Heilk.  (Inn.  Med.),  24,  70,  1903. 

24  R.  Neumeister,  Zeitschr.  f.  Biol.,  24,  272,  1888;  E.  Abderhalden  and 
C.  Oppenheimer,  Zeitschr.  f.  physiol.  Chem.,  42,  155,  1904;  E.  Abderhalden, 
Funk  and  London,  ibid.,  51,  269,  1907 ;  O.  Cohnheim,  Nagel's  Handb.  d.  Physiol., 
2,  626,  1907;  P.  Morawitz  and  R.  Ditschy,  Arch.  f.  exper.  Pathol.,  54,  88,  1906; 
S.  B.  Shryver   (Univers.  College,  London),  Biochem.  Journ.,  1,  123,  1906. 

25  E.  Abderhalden,  Biochem.  Zeitschr.,  8,  368,  1908;  E.  Freund,  ibid.,  7,  361, 
1908;    9,  463,  1908;    11,  541,  1908. 


ALBUMOSES  AND  AMINOACIDS  57 

Resorption  of  Iodized  Proteins. — The  author,  in  associ- 
ation with  M.  Friedmann,  has  attempted  to  solve  this 
difficulty  by  a  study  of  the  resorption  of  iodized  proteid 
substances.26  Isolation  of  no  particular  metabolic  product 
containing  iodine  was  sought,  but  rather  the  iodine  dis- 
tribution. One  can  in  this  way  determine  after  admin- 
istration of  an  iodized  protein  what  part  of  the  iodine 
present  at  a  given  time  in  the  intestinal  content,  the  intes- 
tinal wall,  in  the  blood  and  urine,  exists  in  the  form  of  in- 
coagulable organic  substances  which  can  be  precipitated  by 
phosphotungstic  acid  (albumoses  and  peptones),  in  the  form 
of  incoagulable  organic  substances  not  precipitated  by  phos- 
photungstic acid  (amino acids) ,  and  finally  how  much  exists 
in  inorganic  combination.  The  results  obtained  indicate 
that  at  least  the  bulk  of  the  determined  iodo-proteid  sub- 
stance (iodo-proteic  acid)  in  absorption  from  the  intestine  of 
a  cat  is  so  completely  dissociated  that  the  iodine  in  the 
intestinal  wall  and  blood  appears,  not  in  form  of  iodized 
albumoses  or  peptones,  but  as  inorganic  alkali  iodides. 

Objections  to  the  Resorption  of  Albumoses  and  Amino- 
acids. — Otto  Loewi 27  has  pointed  out  that  as  a  matter  of  fact 
the  toxicity  of  albumoses  and  peptones  introduced  directly 
into  the  blood  circulation  (referring  to  the  reduction  of  blood 
coagulability  and  the  lowering  of  vascular  tone  in  the 
splanchnic  area,  shown  by  the  investigations  of  Schmidt- 
Mühlheim,  Fano  and  others)  is  contradictory  to  the  idea 
that  albumin  is  taken  up  in  the  form  of  peptone.  To  the 
objection  that  any  important  formation  of  aminoacids  in  the 
intestine  would  represent  a  waste  of  chemical  tension  energy 
lost  to  no  purpose  in  the  splitting  process,  Loewi  has  shown 
from  Rubner's  calorimetric  determinations  that  in  such  a 
process  certainly  not  above  10  per  cent,  of  energy  is  lost, 

26  O.  v.  Fürth  and  M.  Friedmann  (Vienna),  Arch.  f.  exper.  Pathol. 
(Schmiedeberg's  Festschrift),  p.  214,  1908. 

27  O.  Loewi  (H.  H.  Meyer's  Labor.,  Marburg),  Arch.  f.  exper.  Pathol., 
48,  327,  1902. 


58  PROTEIN  DIGESTION  IN  THE  INTESTINE 

and  therefore  that  it  is  not  in  any  sense  a ' '  purposeless  waste 
of  energy." 

Residual  Nitrogen. — It  might  very  properly  be  supposed 
that,  in  case  the  aminoacids  resulting  from  the  advanced  pro- 
tein dissociation  are  actually  resorbed  as  such,  it  would  be  a 
matter  of  little  difficulty  in  an  animal  in  the  midst  of  diges- 
tive activity  to  detect  a  notable  increase  of  residual  nitrogen 
in  the  blood  in  the  form  of  incoagulable  compounds.28  As  a 
matter  of  fact,  however,  this  is  very  difficult.  G.  v.  Bergman 
and  Langstein 29  have  calculated  that,  if,  as  supposed,  tissue 
assimilation  proceeds  in  full  harmony  with  resorption,  only  a 
few  hundredths  of  one  per  cent,  of  aminoacids  in  the  portal 
blood  will  suffice  to  cover  the  total  nitrogen  transportation 
from  intestine  to  the  blood  required  for  protein  metabolism. 
0.  Cohnheim  believes  that  it  may  be  concluded  from  observa- 
tions upon  the  rapidity  of  meat  digestion  and  the  rapidity  of 
blood  circulation  that  even  with  the  most  active  absorption 
and  if  no  other  tissues  were  involved  not  more  than  0.03  g. 
of  albumin  or  protein  dissociation  products  could  be  taken 
up  in  a  litre  of  blood.30  According  to  an  investigation  con- 
ducted under  the  direction  of  Hofmeister31  the  residual 
nitrogen  of  the  blood  may  be  reduced  to  three  fractions: 
urea,  "albumoses"  precipitable  by  tannin,  and  aminoacids 
(not  precipitated  by  tannin) .  The  bulk,  actually  about  three- 
fourths,  of  the  residual  nitrogen  in  the  blood  of  either  the 
fasting  or  of  the  digesting  dog,  consists  of  urea.  Of  the 
other  two  fractional  parts  that  of  the  aminoacids  always 
shows  definite  increase  during  digestion.  The  albumose 
fraction  is  an  inconstant  one ;  even  after  feeding  albumoses 
no  increase  was  noted  indicative  of  their  entrance  to  the 

28  Literature  upon  the  Incoagulable  Nitrogen-containing  Bodies  of  the 
Blood  Serum:  P.  Morawitz,  Handb.  d.  Biochem.,  2",  80-86,  1909. 

29 1.  c. 

30  O.  Cohnheim,  Physiol,  d.  Verd.  u.  Ernähr.,  p.  227,  1908. 

31 H.  Hohlweg  and  H.  Meyer  (Physiol.  Chem.  Instit.,  Strassburg),  Hof- 
meister's  Beitr.,  11,  381,  1908. 


SYNTHESIS  OF  THE  PRODUCTS  OF  DIGESTION       59 

blood  in  unsplit  state.  Folin  found  on  resorption  of  glyco- 
coll  or  alanin  from  the  stomach  or  large  intestine  an  increase 
in  the  residual  nitrogen,  usually  too  of  the  urea,  in  the 
blood.32 

There  is  another  series  of  observations  which  are  at 
least  not  contradictory  to  the  supposition  that  the  amino- 
acids  pass  into  the  blood.  Pringle  and  Cramer 3S  found  the 
blood  of  a  digesting  animal  to  contain  a  somewhat  higher 
residual  nitrogen  than  that  of  a  fasting  animal.  Embden 
and  his  pupils  have  been  able  to  detect  the  presence  of  small 
quantities  of  aminoacids  in  the  blood  and  their  passage 
into  the  urine  by  means  of  the  naphthalin-sulphochloride 
method.34  In  pathological  states  the  aminoacids  in  the 
blood  can  doubtless  be  increased.  According  to  Neuberg 
and  Richter35  in  acute  yellow  atrophy  of  the  liver  amino- 
acids may  be  found  in  such  quantities  as  to  suggest  that 
perhaps  in  some  way  owing  to  the  loss  of  hepatic  function 
a  further  change  of  the  catabolic  products  of  proteids  (split 
in  the  intestine  into  crystallizable  products)  fails  to  take 
place.  In  uraemia,  too,  at  times  the  aminoacids  are  appar- 
ently increased  in  the  blood. 

Moreover  it  should  not  be  overlooked  that  0.  Cohnheim 36 
in  his  studies  upon  invertebrates,  octopods  particularly, 
came  to  the  conclusion  that  albumin  is  completely  catabol- 
ized  in  the  intestine  and  resorbed  in  the  form  of  aminoacids. 
These  may  thereafter  according  to  requirements  undergo 
either  combustion  or  synthesis  in  the  tissues. 

Synthesis  of  the  Products  of  Digestion. — Assuming 
then,  as  we  seem  fully  justified  in  doing,  that  the  dietary 
protein  undergoes  an  advanced  grade  of  cleavage  in  the 

;:0.  Folin,  W.  Denis  and  H.  Lymann  (Harvard  Med.  School),  Journ.  of 
Biol.  Chem.,  12,  141,  253,  259,  1912. 

53  H.  Pringle  and  W.  Cramer,  Journ.  of  Physiol.,  37,  158,  1908. 

'-*  G.  Embden  and  H.  Reese,  Hofmeister's  Beitr.,  7,  411,  1905:  A.  Bingel, 
Zeitschr.  f.  physiol.  Chem.,  57,  382,  1908. 

35  C.  Neuberg  and  Richter,  Deutsche  med.  Wochenschr.,  190 Jf,  499. 

56  0.  Cohnheim,  Xagel's  Handb.  d.  Physiol.,  2,  629,  1907. 


60  PROTEIN  DIGESTION  IN  THE  INTESTINE 

intestine,  the  further  question  arises  whether  the  re- 
sultant cleavage-products  do  not  undergo  either  locally  in 
the  intestinal  wall  or  in  their  passage  thence  into  the  blood 
a  synthetic  reconstruction  in  such  manner  that  the  nitrogen 
from  the  intestine  comes  to  be  found  in  the  circulatory  fluids, 
not  in  the  form  of  aminoacids,  but  in  high-molecular  com- 
binations. Attention  may  be  called  to  the  fact  that  Van 
Slyke 37  has  recently  applied  his  delicate  nitric  acid  method 
of  determination  of  the  aliphatic  amino-group  (cf.  Vol.  I  of 
this  series,  Chemistry  of  the  Tissues,  p.  18)  to  the  detec- 
tion of  aminoacid  nitrogen  in  the  blood.  By  this  method  it 
has  been  established  that  even  large  amounts  of  aminoacids 
injected  intravenously  disappear  very  quickly  from  the 
blood  without  anything  like  an  important  part  appearing  in 
the  urine.  For  example,  of  twelve  grams  of  alanin  injected 
intravenously  there  remained  after  half  an  hour  only  a  few 
decigrams  in  the  blood,  the  rest  being  apparently  transferred 
into  the  tissues.  Van  Slyke  concludes  from  his  investiga- 
tions that  the  supposition  of  synthetic  change  of  the  amino- 
acids in  the  bowel  wall  is  superfluous  and  that  the  smallness 
of  the  increase  of  aminoacids  in  the  blood  of  digesting  ani- 
mals is  entirely  explicable  by  the  avidity  with  which  these 
substances  are  taken  up  by  the  tissues  and  further  elaborated 
by  them. 

The  results  obtained  by  efforts  to  arrive  at  a  conclusion 
in  regard  to  synthetic  processes  from  analytic  comparison 
of  the  composition  of  the  intestinal  mucous  membrane  of 
fasting  and  digesting  animals  are  in  no  sense  consistent.38 
It  should  always  be  remembered,  however,  that  a  number  of 
direct  observations  indicate  the  possibility  of  condensation 
processes  in  the  intestine. 

37  D.  D.  Van  Slyke,  and  G.  M.  Meyer  (Rockefeller  Instit.,  New  York), 
Journ.  of  Biol.  Chem.,  12,  399,  1912. 

88  F.  Botazzi,  Arch,  di  Fisiol.,  5,  317,  1908;  cited  in  Biochem.  Centralbl., 
8,  374,  1908;  E.  S.  London,  Zeitschr.  f.  physiol.  Chem.,  61,  69,  1909;  P. 
Glagolew  (St.  Petersburg),  Biochem.  Zeitschr.,  32,  222,  1910. 


SYNTHESIS  OF  THE  PRODUCTS  OF  DIGESTION       61 

Kutscher  and  Seemann39  have  determined  that  rela- 
tively simple  abinret  substances  are  included  in  the  ex- 
tractives of  the  intestine,  which  split  when  treated  with  boil- 
ing mineral  acids  with  the  production  of  leucin  in  consider- 
able amounts.  This  observation  may  perhaps  have  some  bear- 
ing upon  the  possibility  of  the  leucin  from  the  intestinal 
mucous  membrane  (and  of  many  other  simple  products  of 
protein  cleavage)  having  previously  undergone  a  process  of 
coupling  directly  in  the  intestinal  wall.  Bearing  upon  con- 
densation processes,  the  extensive  observations  of  Danilew- 
ski  and  his  students  (vide  supra,  p.  30)  upon  plastein 
formation  should  be  noted.  In  albumose  solutions  autolysed 
with  intestinal  mucous  membrane  an  increase  of  coagulable 
nitrogen  at  the  expense  of  incoagulable  nitrogen  has  been 
found,40  interpreted  tentatively  as  transformation  of 
albumoses  into  serum  albumin.  A  mixture  of  the  digestion- 
products  of  casein  has  been  observed  to  "jell"  under  the 
influence  of  intestinal  secretion  supposedly  due  to  the  action 
of  a  ferment.41  Ernst  Freund  observed  that  upon  bringing 
together  fresh  horse-serum  and  a  solution  of  Witte 's  pep- 
tone a  portion  of  the  albumoses  become  coagulable,  and, 
further,  that  of  the  serum-proteins  only  euglobulin  shows 
this  characteristic,  and  that  after  addition  of  the  peptone  to 
serum  the  euglobulin  fraction  diminishes,  while  the  pseudo- 
globulin  and  albumin  fractions  increase.42  Italian  authors 
have  stated  that  precipitates  are  given  by  various  tissue  ex- 
tracts, some  with  blood-serum,  some  with  peptone ;  and  have 
suggested  the  former  type  of  precipitation  as  an  expression 
of  a  binding  of  the  circulating  dietary  protein  with  the 
tissue  proteins.43 

"*  F.  Kutscher  and  J.  Seemann  (Physiol.  Instit.,  Marburg),  Zeitsch.  f. 
physiol.  Chem.,  85,  432,  1902. 

•  Grosmann  (Kurajeff's  Lab.,  Charkow),  Hofmeister's  Beitr.,  6,  192,  1905. 

41 E.  S.  London,  Zeitschr.  f.  physiol.  Chem.,  74,  301,  1911. 

42  E.  Freund,  Wiener  med.  Wochenschr.,  1905,  No.  47 ;  1909,  108. 

•"Pacchioni  and  Carlini  (Pediatric  Clinic,  Florence),  Arch,  di  Fisiol.,  2, 
297,  1905;    abstract,  Biochem.  Centralbl.,  4,  1490,  1905-06. 


62  PROTEIN  DIGESTION  IN  THE  INTESTINE 

Interesting  as  such  observations  in  themselves  may  be, 
the  greatest  caution  should  be  observed  in  interpreting  their 
physiological  significance.  That  the  physico-chemical  rela- 
tions in  as  complicated  colloid  system  as  blood  serum  on  the 
addition  of  a  second,  no  less  complex  system,  like  Witte 's 
peptone,  may  be  decidedly  disturbed  is  in  nowise  surprising. 
It  is  very  questionable  whether  any  sort  of  conclusion  is 
justifiable  from  such  static  change  as  to  the  actual  physiology 
of  absorption. 

Parenteral  Introduction  of  Protein. — E.  Freund  44  is  of 
the  opinion  that  the  very  fact  of  elaboration  of  parenterally 
introduced  albumoses  by  the  tissues,  etc.,  bespeaks  collabor- 
ation of  the  intestine.  "Five  minutes  after  intravenous 
injection  of  Witte 's  peptone,  renal  elimination  being  pre- 
vented, only  about  half  the  injected  substance  remains  in  the 
blood.  The  fate  of  the  peptone  remaining  in  the  blood  appar- 
ently depends  upon  whether  or  not  the  intestinal  blood  ves- 
sels be  traversed  or  not.  If  these  are  closed  off  the  great 
bulk  of  the  injected  incoagulable  substance  remains  in  the 
blood  .  .  ."  Other  experiments,45  as  those  conducted  by 
von  Körösy,  upon  the  fate  of  parenterally  introduced  pro- 
teins in  conditions  of  intestinal  exclusion  are,  however,  not 
confirmatory  of  Freund 's  assertion;  according  to  these  all 
protein  to  undergo  cleavage  in  the  organism  must  first  pass 
the  intestine  and  there  undergo  a  particular  preparation. 

Eeturning  to  the  major  question,  as  to  the  ability  of  the 
intestine  to  dissociate  protein  to  its  elementary  building- 
stones:  there  can  no  longer  be  the  least  doubt  of  this  if 
Abderhalden^  investigations  are  to  be  accepted.46  The 
older  view  that  proteid  nitrogen  is  absorbed  exclusively  in 
the  form  of  ' '  albumoses ' '  and  ' '  peptones ' '  is  no  longer  ten- 
able in  the  light  of  this  knowledge.    Another  question,  how- 

44  E.  Freund  and  H.  Popper,  Biochem.  Zeitschr.,  15,  272,  1909 ;  G.  Töpfer, 
Zeitschr.  f.  experimental  Pathol.,  3,  45,  1906;  E.  Freund  and  G.  Töpfer,  ibid., 
S,  633,  1906;    E.  Freund,  ibid.,  4,  1,  1907. 

45  K.  v.  Körösy   (Budapesth),  Zeitschr.  f.  physiol.  Chem.,  62,  68,  1909. 
40  Cf.  E.  Abderhalden,  Zeitschr.  f.  physiol.  Chem.,  7  4,  436,  1911. 


PROTEIN  SYNTHESIS  FROM  CLEAVAGE  PRODUCTS     63 

ever,  upon  which  there  is  no  unanimity,  is  to  what  stage 
maximal  cleavage  actually  proceeds  in  physiological  condi- 
tions.   Many  authors  retain  the  older  view  "that,"  as  E. 
Freund 47  says,  "the  body  does  not  follow  a  single  restricted 
principle,  but  manifests  a  many-sided  ability  in  correspon- 
dence with  the  varying  demands  upon  it."    "Just  as  in 
ordinary  household  activities  there  is  need  not  only  of  small 
firewood  but  also  of  larger  timber,  so  the  organism  makes 
use  of  the  protein  material  in  form  of  all  kinds  of  cleavage- 
products  without  first  reducing  all  to  the  smallest  grade." 
Protein  Synthesis  from  Products  of  Advanced  Cleavage 
of  Protein. — The  view  that  all  protein  undergoes  advanced 
cleavage  before  resorption  assumes  the  possibility,  for  main- 
tenance of  the  body  in  nitrogen  equilibrium,  of  its  being  pro- 
vided, not  with  protein,  but  with  the  sum  total  of  the  lowest 
products  of  protein  cleavage.     The  credit  of  having  first 
experimentally  proved  this  possibility  belongs  to  Otto  Loewi. 
In  1902  Loewi,  working  in  the  laboratory  of  Hans  Horst- 
Meyer,  showed  experimentally  by  feeding  with  pancreatic 
tissue  autolysed  to  the  point  of  loss  of  biuret  reaction  that 
the     aggregate     of     the     biuret-free     end-products     can 
be  substituted  for  dietary  protein  (that  is,  enters  into  the 
composition  of  every  part  of  the  body  protein  undergoing 
metabolic    disintegration).48     At    first    this    fundamental 
proposition  was  received  with  widespread  doubt ;  but  later, 
especially  following  the  experiments  of  Henriques  and  Han- 
sen49 and,  above  all,  the  studies  of  Abderhalden  and  his 
school  it  has  been  adopted  as  beyond  doubt.50 

47  E.  Freund.,  Wiener  klin.  Wochenschr.,  1905,  No.  47. 

** O.  Loewi  ( Pharmacolog.  Instit.,  Marburg),  Arch.  f.  exper.  Pathol.,  58, 
303,  1902. 

«»V.  Henriques  and  C.  Hansen,  Zeitschr.  f.  physiol.  Chem.,  -J5,  417,  1904; 
49,  113;    5k,  406,  1907. 

60  Literature  upon  the  Synthesis  of  Protein  from  the  Low  Protein  Cleavage 
Products:  H.  Lüthje,  Ergebn.  d.  Physiol.,  7,  805-830,  1904;  P.  Rona,  Handb. 
d.  Biochem.,  4',  540-560,  1910;  E.  Abderhalden,  Synthesis  of  Cellular  Building 
stones  in  Plant  and  Animal,  Berlin,  J.  Springer,  1912,  128  pp. 


64  PROTEIN  DIGESTION  IN  THE  INTESTINE 

Abderhalden^  Experiments. — Abderhalden  and  his  asso- 
ciates have  by  a  long  series  of  carefully  conducted  experi- 
ments so  fully  solved  many  of  the  problems  relating  to  this 
field  of  our  study  that  it  is  possible  to  regard  it  as  fairly 
comprehensible.  It  is  known  today  that  by  appropriate 
and  long  continued  combined  action  of  pepsin,  trypsin 
and  erepsin  proteid  matter  may  be  completely  (that  is, 
comparably  to  total  acid  hydrolysis)  dissociated,  and  that 
a  mixture  of  the  products  of  such  process  is  capable  of 
maintaining  in  nitrogen  equilibrium  for  many  weeks  ani- 
mals and  human  beings,  whether  in  course  of  growth,  in 
conditions  of  pregnancy  or  of  lactation.  The  integrity  of 
the  hepatic  function  is  moreover  not  a  matter  of  necessity 
in  connection  therewith ;  for  Abderhalden  and  London  were 
able  to  maintain  in  nitrogen  balance  a  dog  with  Eck 's  fistula 
upon  a  diet  made  up  of  advanced  protein  cleavage  prod- 
ucts. Contrary  to  the  belief  that  only  the  aggregate  of  split 
products  from  digestive  ferment  action  and  not  those  from 
acid  hydrolysis  are  capable  of  replacing  protein,  Abder- 
halden has  been  able  to  keep  in  full  nutrition  for  fourteen 
days  a  dog  fed  upon  meat  completely  hydrolysed  by  boiling 
with  strong  sulphuric  acid.  Bemoval  of  tryptophane  from 
the  mixed  digestive  products  rendered  the  mixture  unfit  for 
maintenance  of  nitrogen  balance.  The  same  inefficiency  was 
found  in  employing  a  mixture  of  aminoacids  obtained 
by  cleavage  of  silk,  this  proteid  being  characterized  by 
its  high  proportion  of  glycocoll,  alanin  and  tyrosin,  and  its 
poverty  in  a  number  of  the  important  "building  stones"  of 
the  typical  protein  molecule.  Similar  results  were  obtained 
with  gelatine,  a  substance  rich  in  glycocoll,  containing  very 
little  alanin,  and  neither  tyrosin  nor  tryptophane.  If  the 
glycocoll  of  the  split  gelatine  is  proportionately  diluted  by 
addition  of  the  other  building-stones  which  occur  in  small 
quantities  the  combination  may  be  made  to  be  entirely 
equivalent  to  protein.  It  may  be  questioned  whether  the 
dissociated  protein  is  capable  of  replacing  normal  protein 


ABDERHALDENS  EXPERIMENTS  65 

not  only  in  a  qualitative  but  also  in  a  quantitative  sense. 
Experiments  of  E.  Voit  and  Zisterer,51  in  which  the  matter 
of  "economy"  comes  forward,  apparently  bear  upon  this 
point,  uncleft  casein  being  superior  to  digested  casein  and 
the  latter  superior  to  casein  hydrolyzed  by  acid.  With  ad- 
vance of  cleavage  the  physiological  nutritive  value  of  a  sub- 
stance apparently  decreases,  larger  and  larger  amounts  at 
any  rate  being  required  for  maintenance  of  nitrogen  balance. 
On  the  other  hand  a  recent  series  of  experiments  by  Abder- 
halden, Frank  and  Schittenhelm  would  indicate  that  protein 
equivalence  of  the  combined  cleavage  products  is  a  complete 
one.  Acquiescence  may  be  granted  to  the  first  of  these  in- 
vestigators only  in  the  sense  that  positive  results  in  such 
experiments  are  always  of  more  significance  than  are  nega- 
tive ones.  Experiments  carried  on  by  Buglia 52  in  Botazzi's 
laboratory  clearly  confirm  the  view  that  the  products  of 
meat  digestion  can  be  substituted  for  the  meat  itself  without 
noteworthy  difference  of  result  in  nitrogen  fixation  and  in- 
crease of  body  weight  in  growing  animals. 

Finally  Abderhalden  in  a  very  interesting  experiment 
has  fed  animals  upon  a  general  diet,  not  merely  proteid  sub- 
stances, in  state  of  complete  cleavage.  Dogs  were  given,  be- 
sides the  fully  split  protein,  the  cleavage  products  of  fat 
(glycerol  and  the  higher  fatty  acids),  monosaccharids, 
cholesterol,  the  structural  units  of  nucleinic  acid  and  the 
necessary  ash  constituents.  In  the  course  of  experiments 
extending  over  more  than  two  months  the  experiment  ani- 
mals not  only  maintained  their  nitrogen  equilibrium  but 
actually  increased  in  weight. 

This  is  an  example  of  indefatigable  and  purposeful  labor 
ending  in  the  solution  of  a  great  problem.    If  one  reflects, 

51  E.  Voit  and  J.  Zisterer  (Veterinary  School,  Munich),  Zeitschr.  f.  Biol., 
58,  457,  1910. 

62  G.  Buglia  (F.  Bottazi's  Lab.,  Naples),  Zeitschr.  f.  Biol.,  57,  365,  1911. 

5 


66  PROTEIN  DIGESTION  IN  THE  INTESTINE 

we  may  often  find  that  the  very  greatest  advances  in 
physiology  may  be  formulated  in  a  few  simple  words ;  in  this 
case  they  run:  "the  problem  of  the  role  of  foodstuffs  of 
complicated  structure  is  solved  by  their  most  simplified 
structural  units."  53 

Application  of  these  Results  in  Sickroom  Dietary. — 
These  results  are  not  only  of  interest  to  physiologists,  but 
are  of  extreme  importance  in  practical  medicine.  Abder- 
halden, Frank  and  Schittenhelm  54  have  actually  prevented 
nitrogenous  loss  for  weeks  in  a  patient  by  rectal  feeding  with 
beef  split  by  the  combined  action  of  trypsin  and  erepsin 
until  the  biuret  reaction  no  longer  showed.  This  proves  the 
possibility  of  introduction  into  human  beings  of  their  daily 
nitrogenous  requirement  without  bringing  the  parts  con- 
cerned with  protein  cleavage  into  activity.  The  nitrogen 
may  thus  be  introduced  in  fluid  form  in  small  volume  for 
quick  and  complete  resorption.  It  may  be  predicted  that  in 
the  future  the  employment  of  preparations  of  this  sort  will 
find  a  field  in  the  treatment  of  gastric  ulcer,  stenoses,  can- 
cerous and  ulcerous  processes  of  any  sort  wherever  they  may 
exist  in  the  digestive  tube.  Where  there  is  occasion  to  spare 
the  digestive  tract,  theoretically  it  is  unquestionably  more 
rational  to  introduce  the  physiologically  definite  mixture  of 
the  end  products  of  protein  cleavage  than  to  administer  the 
usually  indefinite  prepared  foods  with  which  people  in  re- 
cent years  have  been  so  richly  favored  (largely  through  in- 
sistent laudatory  advertising  and  in  a  much  less  measure 

53  E.  Abderhalden,  Synthese  der  Zellbausteine  in  Pflanz  und  Tier,  p.  74,  Ber- 
lin, J.  Springer,  1912.  Cf.  therein  (pp.  116-118)  a  summary  of  the  studies 
conducted  by  Abderhalden  in  association  with  P.  Bona,  B.  Oppler,  E.  S.  London, 
J.  Olinger,  E.  Meszner,  H.  Windrath,  F.  Frank,  A.  Schittenhelm,  F.  Glamser,  D. 
Manoliu,  and  A.  Suwa.     Cf.  also  Zeitschr.  f.  physiol.  Chem.,  77,  22,  1912. 

ME.  Abderhalden,  F.  Frank  and  A.  Schittenhelm,  Zeitschr.  f.  physiol. 
Chem.,  63,  214,  1909;  F.  Frank  and  A.  Schittenhelm  (Med.  Clinic,  Erlangen), 
Münchener  med.  Wochenschr.,  1911,  1288;  Therap.  Monatsch.,  26,  112,  1912. 


AMIDES  IN  METABOLISM  OF  VEGETARIANS         67 

upon  the  ground  of  actual  scientific  investigation).  Of 
course  every  soluble  protein  preparation  has  in  the  end  a  cer- 
tain ' ' nutritional  value ' ' ;  whether  the ' ' nutritional  value"  in 
any  individual  case  bears  any  direct  proportion  to  the  price 
charged  for  the  preparation  is  a  matter  which  may  here  be 
gladly  omitted.  Unfortunately,  however,  as  far  as  odor  and 
flavor  are  concerned,  the  applicability  of  the  cleavage  prod- 
ucts of  protein  is  far  from  what  one  would  wish;  and 
moreover,  perhaps  because  of  amines  present,  a  variety  of 
collateral  effects  are  likely  to  appear  and  for  the  present  de- 
tract from  the  therapeutic  appreciation  of  these  substances. 

After  what  has  been  said  above,  the  possibility  of  various 
nitrogenous  substances  serving  as  partial  substitutes  for 
protein  in  nutrition  may  be  readily  understood.  A  number 
of  investigations  bearing  upon  this  point,  concerning  the 
nutritive  value  of  leucin,  various  albumoses,  peptones,  pro- 
tamines, etc.,  have  been  published.05  It  may  at  least  be  seen 
that  such  preparations  may  serve  to  conserve  protein  and 
that  their  value  as  more  or  less  complete  substitutes  for  pro- 
tein must  primarily  depend  upon  just  what  and  how  many  of 
the  metabolically  essential  structural  units  of  the  protein 
molecule  are  missing  from  their  atomic  grouping. 

Relation  of  Amides  in  Metabolism  of  Vegetarians;  Pro- 
tein Synthesis  from  Ammonium  Salts. — Although  the  above 
questions,  at  least  in  a  fundamental  way,  seem  fairly  solved, 
this  certainly  cannot  be  said  of  another  matter,  the  relation  of 
the  amides  and  aminoacids  in  metabolism.  Because  of  the 
wide  distribution  of  aminoacids  and  amides  in  plants  and 
owing  to  the  fact  that  the  determination  of  the  value  of  the 
various  foodstuffs  (as  turnips, molasses, etc.)  is  of  very  great 

55  A.  Ellinger  (Physiol.  Instit.,  Munich),  Zeitschr.  f.  Biol.,  33,  201,  1896; 
L.  Blum  (Hofmeister's  Lab.),  Inaug.  Diss.,  Strassburg,  1901;  V.  Henriquez 
and  C.  Hansen,  Zeitschr.  f.  physiol.  Chem.,  48,  383,  1906;  49,  113,  1906;  P. 
Bona  and  W.  Müller,  ibid.,  50,  2G3,  1906;  J.  B.  Murlin,  Amer.  Journ.  of 
Physiol.,  20,  234,  1907-08;  cf.  therein  literature  appended. 


68  PROTEIN  DIGESTION  IN  THE  INTESTINE 

practical  interest  in  agriculture,  an  unusually  large  number 
of  studies  have  been  directed  to  the  question  of  how  far 
amides,  especially  as  par  agin  (as  W.  Völtz  and  others  have 
maintained),  are  capable  of  replacing  the  protein  of  food.56 
It  is  readily  appreciable  that  amides  and  aminoacids  may 
serve  as  conservers  of  protein.  There  is,  however,  a  con- 
stantly recurring  idea  that  at  least  in  herbivora  protein  may 
be  replaced  by  such  amides.  N.  Zuntz,  0.  Hagemann  and 
other  writers  would  find  the  key  to  the  whole  problem  in  the 
role  of  the  intestinal  bacteria.  Introduction  of  asparagin 
and  similar  substances  they  believe  not  only  serves  to  con- 
serve protein  and  preserve  the  dietary  protein  from  the  influ- 
ence of  the  bacteria;  but  the  amides  are  a  medium  from 
which  the  bacteria  because  of  their  plant  characteristics  are 
able  to  construct  protein.  If  in  the  end  the  bacteria  die,  this 
protein  of  theirs  is  of  advantage  to  the  vertebrate  animal. 
In  this  manner  not  only  asparagin,  but  ammonium  acetate 
and  many  other  ammonium  salts  may  indirectly,  of  course, 
become  a  source  of  protein  for  the  animal  body.  In  the 
course  of  the  last  few  months  the  question  of  the  availability 
of  ammonium  salts  and  amides  to  enter  into  protein  synthesis 
has  been  brought  into  prominence  from  the  studies  of 
E.  Gräfe  and  of  Abderhalden. 

E.  Gräfe  and  Schläpfer  from  extensive  metabolic  studies 
determined  that  in  dogs  receiving  a  full  diet  of  non- 
nitrogenous  material  not  only  nitrogen  balance  but  actual 
nitrogen  retention  and  increase  of  weight  can  be  obtained  by 
feeding  ammonium  citrate,  without  subsequent  outpouring 

60  K.  Anderlik,  K.  Velich  and  VI.  Stanek,  K.  Friedländer,  S.  Gabriel,  O. 
Hagemann,  V.  Henriques  and  C.  Hansen,  J.  Just,  0.  Kellner,  C.  Lehman, 
A.  Morgen,  C.  Beger  and  F.  Westhauser,  Mauthner,  M.  Müller,  J.  Munck,  E. 
Peschek,  G.  Politis,  B.  v.  Strusiewicz,  F.  Rosenfeld,  VV.  Tkär,  W.  Völtz,  H. 
Weiske,  N.  Zunz.  Literature:  H.  Lüthje,  Ergebn.  d.  Physiol.,  7,  828-830, 
1908;  E.  Abderhalden,  Vorlesungen,  2d  ed.,  pp.  301-303,  1909;  P.  Rona,  Handb. 
d.  Biochem.,  //,  554-559,  1911;  E.  Peschek  (Zootech  Instit.  of  Agricul.  School, 
Berlin),  Pflüger's  Arch.,  llß,  143,  1911. 


AMMONIUM  SALTS  IN  PROTEIN  SYNTHESIS         69 

of  the  retained  nitrogen  taking  place.57  It  would,  however, 
be  decidedly  misleading  to  regard  this  as  evidence  indicating 
protein  synthesis  from  ammonia  and  nitrogen-free  material. 

The  above  findings  have  been  confirmed  by  independent 
observations  of  Abderhalden  to  the  extent  that  after  addi- 
tion of  ammonium  acetate  to  a  nitrogen-free  diet  consisting 
of  rich  fatty  and  carbohydrate  constituents  there  may  ensue 
a  nitrogen  retention.58 

In  connection  with  the  observations  (to  be  discussed  later 
in  detail)  of  Knoop,  Embden  and  their  associates  upon  the 
transformation  of  a -ketonic  acids  into  aminoacids  by  the  fol- 
lowing schema: 

R— CH2  R— CH, 

I  I 

CO+NH,    T^:    CH  NHg+O 

I  I 

COOH  COOH, 

it  is  not  difficult  to  think  of  a  shifting  of  the  equation  between 
aminoacids  and  ketonic  acids  by  the  introduction  of  am- 
monia in  a  way  to  bring  about  synthesis  of  aminoacids,  the 
ketonic  acids,  however,  to  be  derived  from  nitrogen-free 
food  constituents. 

In  further  studies  59  Abderhalden,  however,  pointed  out 
that  it  is  a  matter  of  great  difficulty  to  draw  any  consistent 
conclusion  from  the  results.  In  reality  it  turned  out  that 
even  without  nitrogen  administration  he  was  able  by  full 
diet  of  carbohydrates  and  fats  to  maintain  for  a  long  time 
constant  body  weight  and,  in  fact,  for  short  periods  to 
induce  increase  of  weight  of  the  experiment  animals;  so 
that  apparently  it  is  inadmissable  to  come  to  any  conclusions 
as  to  protein  synthesis  after  administration  of  ammonium 
salts  whether  there  be  weight  loss  or  weight  increment. 

57  E.  Gräfe,  Kongr.  f.  innere  Med.,  Wiesbaden,  1912;  E.  Gräfe  and  V. 
Schlüpfer,  Zeitsch.  f.  physiol.  Chem.,  77,  1,  1912;  E.  Gräfe,  ibid.,  78,  485,  1912; 
cf.  claim  for  priority  by  W.  Völtz,  ibid.,  79,  415,  1912. 

58  E.  Abderhalden,  ibid.,  7S,  1,  1912. 

K  E.  Abderhalden  and  P.  Hirsch,  Zeitschr.  f.  physiol.  Chem.,  80,  136,  1912. 


70  PROTEIN  DIGESTION  IN  THE  INTESTINE 

In  another  series  of  experiments  60  Abderhalden  fed  gela- 
tin which  is  not  a  full  equivalent  for  protein  because  the  ani- 
mal cells  are  apparently  unable  to  fonn  de  novo  certain  build- 
ing stones  which  are  absent  from  gelatin.  He  then  sought 
to  increase  the  chance  of  protein  synthesis  in  the  organism 
during  a  full  diet  of  carbohydrates  and  fats  by  adding  am- 
monium acetate  to  the  gelatin.  But  the  nitrogen  record 
constantly  remained  negative.  "From  these  experimental 
results  we  may  conclude,"  he  says,  "that  the  basis  for 
protein  synthesis  is  not  to  be  found  in  ammonium  salts  with 
carbohydrate  or  fatty  material. ' ' 

London's  Studies. — It  is  impossible  to  conclude  the  sub- 
ject of  protein  digestion  in  the  intestine  without  special  con- 
sideration of  the  investigations  which  for  years  E.  S.  London 
with  a  number  of  collaborators  has  been  conducting  in  the  In- 
stitute of  Experimental  Medicine  in  St.  Petersburg.  London 
has  developed  the  technic  of  intestinal  fistulas  to  a  high  de- 
gree of  perfection.  He  is  not  satisfied  to  provide  a  single 
fistula  in  the  experimental  animal ;  his  "  polyfistulous  dogs ' ' 
enable  him  to  make  comparative  studies  of  various  intestinal 
levels  at  one  given  time ;  his  "  panchymotic  dog, ' '  wearing  in 
addition  to  a  double-chambered  duodenal  canula  a  gastric 
and  a  jejunal  canula,  puts  him  in  position  to  obtain  coinci- 
dently  the  gastric  secretion,  the  bile,  the  pancreatic  juice  and 
the  intestinal  secretion  in  proper  isolation  from  each  other. 

For  a  number  of  years  London  has  been  publishing  the 
results  of  his  studies  in  a  very  long  series  of  contributions 
embracing  a  wealth  of  individual  observations.61  They 
take  up  the  rate  of  protein  catabolism,  the  resorption  inten- 
sity and  movement  of  the  intestinal  contents  in  particular 

60  E.  Abderhalden  and  A.  E.  Lampe,  Zeitsckr.  f.  physiol.  Chem.,  80, 
160,  1912. 

61 E.  S.  London  and  associates,  numerous  publications  in  the  last  thirty 
volumes  of  Zeitschr.  f.  physiol.  Chem. 


LONDON'S  STUDIES  71 

segments  of  the  bowel,  nitrogen  partition  in  the  intestinal 
contents,  the  completeness  of  food  utilization,  the  results  of 
exclusion  of  special  segments  of  the  intestine,  of  the  bile  and 
of  the  pancreatic  secretion,  protein  digestion  in  mixed  diet 
especially  in  presence  of  carbohydrates  and  fats,  the  specific 
adaptation  of  the  digestive  juices  and  the  relative  amounts 
of  enzymes  in  the  intestinal  chyme  in  different  diets,  the  dif- 
ferences between  raw  and  cooked  proteids,  the  behavior  of 
various  proteins  (as  serum  albumin,  egg  albumin,  muscle 
albumin,  casein,  gliadin,  gelatin  and  elastin)  and  of  digestive 
mixtures  (removed  through  a  fistula  from  one  dog  and 
introduced  by  a  fistula  into  another  dog),  the  resorption  of 
individual  aminoacids,  the  mechanism  of  secretory  flow,  the 
influence  of  blood  pressure  and  other  physiological  factors 
upon  secretion  of  the  individual  digestive  juices,  and  other 
similar  subjects.  He  has  endeavored,  too,  to  deduce  a 
mathematically  fixed  relation  between  the  different  secretory 
factors  (as  the  relations  between  the  amount  of  food,  the 
concentration  of  the  gastric  juice,  the  quantity  of  the  bile 
and  pancreatic  juice,  the  alkali-content  of  the  pancreatic  and 
intestinal  secretions,  the  nitrogen-content  of  the  different 
secretions  and  the  digestion  time  of  solid  albumins)  in  which 
as  in  chemistry  of  the  ferments  "quadrate  root  rules"  (in 
Arrhenius'  sense)  play  an  important  part.62 

The  author  confesses  that  he  does  not  regard  himself  as 
fitted  to  criticise  with  full  appreciation  this  remarkable 
wealth  of  undoubtedly  very  valuable  observations.  It  would 
be  a  real  service  were  London  to  take  upon  himself  the  duty 
of  critically  reviewing  them  in  their  proper  relations  and  of 
bringing  out  clearly  the  lines  of  thought  he  has  followed, 
which  are  now  so  divided  among  so  many  separate  publica- 
tions that  the  outsider  is  bound  to  lose  their  connection. 

c2  Consult  also  E.  London  and  C.  Schwarz,  Zeitschr.  f .  physiol.  Chem.,  68, 
34G,  1910;  L.  Popielski,  ibid.,  71,  186,  1911. 


72  PROTEIN  DIGESTION  IN  THE  INTESTINE 

This  done,  we  may  well  hope  that  from  these  studies  and 
others  dealing  with  related  matters  (of  which  special  men- 
tion may  be  made   in   passing  of  those   of   Cohnheim,63 

E.  Zunz,04  Brugsch,05  A.  Scheunert,66  and  K.  Glässner67) 
a  well  rounded  picture  of  protein  dissociation  in  the  intestine 
in  each  of  its  phases  will  gradually  take  shape.68 

Summary. — If  in  conclusion  another  glance  be  cast  back 
over  the  long  way  behind  us,  it  will  be  realized  that  as  the 
actual  accomplishment  of  an  almost  interminable  expendi- 
ture of  effort  and  experimental  work  we  may  say  that  we 
know  that  by  the  combined  action  of  pepsin,  trypsin  and  erep- 
sin  the  protein  in  the  alimentary  canal  can  be  effectively  split 
into  its  most  simple  structural  units  and  that  a  mixture  of 
these  constituent  fragments  is  not  only  qualitatively  but  quan- 
titatively in  every  sense  equivalent  to  the  protein  as  supplied 
intact.  To  be  able  to  say  that  means  something,  but  by 
no  means  all.  Abderhalden  says  very  properly  "that  up 
to  this  time  it  is  entirely  impossible  from  examination  of  the 
intestinal  contents  to  draw  exact  conclusions  as  to  the  degree 
of  catabolism  of  the  food,  because  besides  the  products  of 
complete  cleavage  we  must  take  into  consideration  also  the 
intermediate  substances."  He  states  explicitly,  too,  "from 
our  finding  that  a  combined  mixture  of  aminoacids  is  capable 
of  fully  maintaining  protein  metabolism  for  weeks  and 
months  we  cannot  conclude  at  once   that  necessarily  in 

63  R.  Baumstark  and  O.  Cohnheim  (Physiol.  Instit.,  Heidelberg),  Zeitschr. 
f.  physiol.  Chem.,  65,  477,  483,  1910. 

64  E.  Zunz,  Bulletin  de  l'Acad.  Roy.  de  Med.  de  Belgique,  30,  April,  1910; 
cf.  here  Literature  and  review  of  author's  numerous  earlier  contributions  in 
same  connection. 

65  Th.  Brugsch,  Zeitschr.  f.  exper.  Pathol.,  6,  326,  1909. 

6nA.  Scheunert,  Pfhiger's  Arch.,  121,  169,  1908 ;  139,  131,  1911;  1^1, 
411,  1911. 

67  K.  Glässner  (F.  Kraus'  Clinic,  Berlin),  Zeitschr.  f.  klin.  Med.,  52,  361, 
1904. 

68 Cf.  also  V.  Lieblein  (Prague),  Zeitschr.  f.  Heilk.,  Abt.  f.  Chirurgie,  1906; 

F.  Keller,  Inaug.  Diss.,  Breslau,  1909,  abstract  in  Centralbl.  f.  Physiol.,  23, 
616,  1909. 


SUMMARY  73 

normal  conditions  the  cleavage  of  protein  by  digestion  in 
the  gastro-intestinal  canal  ultimately  extends  to  the  stage  of 
aminoacids. ' ' 69  We  lose  track,  practically  under  our  very 
eyes,  of  the  split  products  of  the  protein  molecule  as  they 
pass  out  from  the  intestine  into  the  blood.  Accumulation 
of  albumoses  or  of  aminoacids  in  the  blood  of  an  individual 
in  the  course  of  digestion  under  entirely  normal  and  physio- 
logical conditions  has  not  been  established  beyond  doubt,  and 
on  the  other  hand  has  not  been  definitely  disproved.  There 
is  some  justification  therefore  in  the  suspicion  that  there 
occurs  a  protein  reconstruction  in  the  wall  of  the  intestine. 
The  author  believes,  too,  that  it  is  by  no  means  improbable 
that  both  the  smaller  and  the  larger  cleavage  products  of  the 
protein  molecule  may  enter  the  circulation,  be  carried  to  the 
various  organs  and  in  the  latter  be  further  elaborated  ac- 
cording to  the  local  requirements,  either  being  condensed 
into  new  protein  molecules,  or  in  further  dissociation  finally 
passing  into  various  end-products  (ammonia,  carbon 
dioxide  and  water). 

The  biological  serum  reactions  (precipitin-reactions.etc.) 
have  led  to  an  appreciation  of  the  almost  endless  multiplicity 
and  specific  peculiarities  of  the  proteid  substances  with 
which  nature  deals.  Axiomatically  we  come  to  the  assump- 
tion, from  the  fact  that  every  individual  contains  in  the 
various  fluids  and  tissues  an  enormous  number  of  chemically 
variant  proteid  substances,  that  doubtless  no  two  different 
kinds  of  animals  contain  exactly  identical  proteins. 

This  tremendous  multiplicity  may  be  appreciated  if  we 
think  of  the  equally  tremendous  number  of  variations  in 
which  the  great  numbers  of  "mosaic  stones"  of  the  protein 
molecule  may  enter  into  combination  in  its  construction. 
That  a  given  individual,  no  matter  the  extreme  variety  of 
Proteids  entering  into  its  food,  is  capable,  always  and  under 

68  E.  Abderhalden,  Synthese  der  Zellbausteine  in  Pflanze  und  Tier,  pp.  53 
and  71,  Berlin,  J.  Springer,  1912;    cf.  Zeitschr.  f.  physiol.  Chem.,  78,  382,  1912. 


74  PROTEIN  DIGESTION  IN  THE  INTESTINE 

all  conditions  and  for  the  whole  period  of  its  life,  of  main- 
taining the  specificity  of  its  own  peculiar  proteins  can  be 
understood  and  conceived  of,  as  far  as  the  author  is  per- 
sonally concerned,  only  by  adopting  the  idea  that  every 
proteid  in  the  food  is  probably,  before  it  can  be  assimilated, 
broken  down  into  aminoaeids.  This  conception  must  be 
acknowledged,  however,  to  be  purely  a  personal  one,  and  is 
offered  only  as  such.  In  the  last  count  every  man  can  think 
only  with  his  own  brain. 


CHAPTER  IV 

PROTEOLYTIC  AND  PEPTOLYTIC  TISSUE  FERMENTS 

AUTOLYSIS 

After  the  consideration  in  the  previous  chapters  of  the 
processes  of  protein  digestion  in  the  stomach  and  intestine, 
and  with  the  future  consideration  of  the  fate  of  the  final 
nitrogenous  cleavage  products  in  the  intermediate  metab- 
olism before  us  in  succeeding  ones,  the  present  discus- 
sion may  very  properly  be  devoted  to  the  protein- 
digesting  tissue  ferments.  At  this  point  study  of  that  mys- 
terious change  which  is  inclusively  spoken  of  as  "autolysis" 
may  serve  in  part  to  bridge  the  great  gap,  or  perhaps  in 
more  exact  verbiage  to  conceal  it,  between  the  two  phases  of 
the  metabolic  process.  It  has  been  pointed  out  that  the  prod- 
ucts of  cleavage  of  the  protein  molecule  are  lost  sight  of  at 
the  very  moment  when  they  are  resorbed  through  the  wall  of 
the  bowel;  and  their  first  traces  reappear  when  the  end- 
products  of  metabolism  begin  to  escape  from  the  body.  That 
which  lies  between  is  the  unexplored  and  completely  un- 
known field  of  the  intermediate  metabolism.  The  hope  of 
throwing  some  light  from  a  single  point  of  view  upon  a  little 
part  of  this  field,  as  with  the  light-cone  of  a  projection  lamp, 
lends  special  interest  to  the  study  of  the  phenomena  of 
autolysis.  Even  if  these  expectations,  at  best  provisional 
ones,  fail  of  fulfilment,  the  enigmatic  process  is  in  itself  suf- 
ficiently interesting  to  temporarily  hold  our  attention. 

As  early  as  1890  Ernst  Salkowski  recorded  the  occur- 
rence of  post  mortem  self -digestion  ("autodigestion")  in 
animal  tissues.  He  noted,  for  example,  that  in  a  pulp- 
like suspension  of  tissue  in  chloroform  water  autodigestive 
processes  take  place,  with  disappearance  of  coagulable 
albumins  to  give  place  to  their  cleavage  products.  Then 
ten  years  later  in  Hofmeister 's  laboratory  Martin  Jacoby  1 

1  M.  Jacoby  (F.  Hofmeister's  Lab.,  Strassburg),  Zeitschr.  f.  physiol.  Chem., 
SO,  149,  174,  1900. 

78 


76  TISSUE  FERMENTS 

investigated  more  exactly  the  bearing  of  these  phenomena  in 
relation  to  various  physiological  and  pathological  processes ; 
since  when  they  have  been  the  subject  of  general  attention. 
Thereafter  "autolysis"  (a  term  introduced  by  Jacoby  which 
has  since  been  adopted  generally)  has  remained  an  important 
subject  in  the  list  of  problems  of  physiological  pathology. 
At  this  point  we  may  as  well  attempt  to  explain  the  process 
in  as  practical  a  manner  as  possible,  whatever  the  outcome. 

Autolysis  a  Complex  Process. — It  is  essential  that  we 
keep  in  mind  that  the  autodigestive  processes  are  really  of 
complex  nature,  for  the  reason  that  they  are  not  the  result  of 
the  isolated  action  of  any  one  given  enzyme  but  of  a  number 
of  ferments.  Side  by  side  in  their  operation  are  the  protein- 
splitting  "tryptases,"  "erepsines"  (concerned  in  complet- 
ing the  dissociation  of  the  high  molecular  cleavage  products 
of  the  protein  molecule),  "arginases,"  ammonia-splitting 
"  deamidases,"  "nucleases"  splitting  the  nucleins,  the  mys- 
terious "oxidases,"  and  besides  these  undoubtedly  many 
more  for  which  we  do  not  even  have  a  name.  It  is  not  at  all 
remarkable  therefore  that  in  the  study  of  autolytic  mixtures 
we  have  to  do  with  a  decidedly  "mixed  group";  along  with 
the  typical  cleavage  products  of  proteins  and  nucleinic  acids, 
and  besides  the  derivatives  of  these  (as  guanidin,  tetra- 
methylendiamin  and  aminobutyric  acid)  are  to  be  met  a 
variety  more  of  products  (as  lactic  acid,  succinic  acid, 
volatile  fatty  acids),  the  origin  of  which  is  by  no  means 
certain.2 

Antiseptic  Difficulty  in  Autolysis  Experiments. — There 
is,  however,  one  very  great  difficulty  in  conducting  ex- 
periments in  autolysis,  namely,  that  of  insuring  antisepsis. 

2  A.  Magnus-Levy,  Hofmeisters  Beitr.,  2,  261,  1902;  S.  Isaak  (F.  Hof- 
meister's  Lab.),  Inaug.  Diss.,  Strassburg,  1904;  M.  Schenk  (Physiol.  Instit., 
Marburg),  Wochenschr.  f.  Brauerei,  1905,  Xo.  16;  abst.  Centralbl.  f.  physiol. 
19,  519,  1905;  P.  A.  Levene,  Zeitschr.  f.  physiol.  Chem.,  Jtl,  393,  1904;  Amer. 
Journ.  of  Physiol.,  11,  437,  1904;    12,  276,  1904. 


AUTOLYSIS  EXPERIMENTS  77 

Only  within  the  last  few  years  has  this  difficulty  come  to  be 
definitely  realized  and  technically  avoided,  thanks  to  the 
studies  of  Salkowski  and  his  pupils.3  For  instance,  it  might 
be  supposed  that  when  a  finely  divided  organ  is  undergoing 
autodigestion  in  a  medium  well  saturated  with  chloroform 
and  toluol,  there  would  be  no  danger  of  the  unwelcome  pres- 
ence of  bacteria.  In  actual  practice,  however,  such  exact 
care  has  by  no  means  been  insisted  upon ;  and  it  has  usually 
been  supposed  that  if  a  few  drops  of  toluol  or  a  few  bits  of 
thymol  were  added  to  a  thick  emulsion  of  some  organ  it  would 
be  quite  safe  to  let  it  stand  in  the  incubator  for  some  months 
and  that  the  danger  of  bacterial  invasion  would  be  surely  and 
for  all  time  eliminated  by  such  a  purely  symbolic  perform- 
ance (for  that  is  actually  about  all  it  represents) .  It  is  quite 
obvious  why  "discoveries"  prospered  and  multiplied  in  our 
literature  on  the  same  scale  as  did  the  bacteria  in  the  pots 
and  jars  of  the  experimenters.  But  in  addition,  even  with 
precautions  to  avoid  such  gross  technical  faults,  other  dif- 
ficulties often  arose  in  the  way  of  microbic  contaminations. 
H.  C.  Jackson  4  pointed  out  that  fresh  canine  livers  even  if 
removed  with  the  utmost  precaution  are  rarely  entirely 
sterile,  but  are  apt  to  contain  an  anasrobic  organism  similar 
to  the  hay  bacillus  which  does  not  grow  on  the  ordinary 
culture  media  but  which  grows  readily  in  "sterile"  tissues. 
Jackson  believes  that  the  appearance  of  lactic  acid,  succinic 
acid,  butyric  acid,  hydrogen  and  sulphuretted  hydrogen  (as 
noted,  for  example,  by  Magnus-Levy  in  "aseptic  autolysis," 
and  their  origin  referred  by  him  to  the  corporeal  carbohy- 
drates and  fats)  is  due  to  the  presence  of  microorganisms  in 
the  autolysing  mixtures.  Here  again  we  are  confronted  with 
that  intolerable  dilemma  besetting  every  point  and  every  side 
of  the  chemistry  of  fermentation :  either  we  are  destroying 
the  normal  physiological  course  of  the  processes  by  introduc- 

3  E.  Salkowski,  Yoshimoto,  Kikkoji  and  others,  Zeitschr.  f.  pkysiol.  Chem., 
63,  109,  1036,  1909. 

4  H.  C.  Jackson,  Journ.  of  Med.  Research,  21,  281,  1909. 


78  TISSUE  FERMENTS 

ing  disinfecting  agents  which  in  the  very  nature  of  things 
cannot  be  without  effect  upon  the  enzymes ; — or  else  we  keep 
on,  making  allowance  as  we  may  for  the  danger  of  bacterial 
invasion. 

Is  Autolysis  the  Continuation  of  an  Intra-vital  Process? 
— It  may  be  assumed  with  certainty  that  no  one  would  have 
devoted  as  much  effort  and  care  to  these  rather  bothersome 
subjects  if  it  were  not  for  the  impression  that  just  here  there 
is  a  chance  to  remove  one  part  of  the  intermediate  metabol- 
ism from  the  dark  interior  of  the  living  economy  into  the 
transparency  of  the  test  tube.  It  was  believed  that  in  the 
phenomena  of  post-mortem  autodigestion  there  may  be  rec- 
ognized a  continuation  of  a  normal  intra-vital  process,  that 
of  the  physiological  protein  dissociation  which  takes  place 
in  the  living  cell.  The  first  point  therefore  to  be  determined 
is  whether  such  a  belief  is  or  is  not  justified.5 

Autolytic  tissue  ferments,  it  must  be  accepted,  have  been 
met  throughout  the  animal  and  vegetable  kingdoms  gen- 
erally, wherever  any  pains  have  been  taken  to  recognize 
them,  in  the  lowest  as  well  as  in  the  most  highly  organized 
living  entities.  Ferments  have  been  differentiated  which, 
on  the  one  hand,  act  best  in  acid  reaction,  and  on  the  other 
those  best  acting  in  alkaline  conditions  a  -  and  ß-proteases 
of  Hedin  and  Rowland).  Vernon  emphasizes  "erepsines" 
above  other  proteases,  and  proposes  to  estimate  the  relative 
amount  of  enzyme  in  tissue  extracts  colorimetrically  by 
application  of  the  biuret  test  (supposing  the  time  required 
to  cause  the  biuret  reaction  to  disappear  from  a  given  quan- 
tity of  a  standard  solution  of  Witte  's  peptone  to  be  in  reverse 
proportion  to  the  amount  of  ferment  present) .     By  compari- 

6  Literature  upon  the  Physiological  Significance  of  Autolytic  Processes: 
M.  Jacoby,  Ergebn.  d.  Physiol.,  1,  225-229,  1902,  and  Handb.  d.  Biochem.,  2', 
175-182,  1910;  E.  Salkowski,  Deutsche  Klinik,  11,  147-182,  1907;  H.  M.  Vernon 
(Oxford),  Ergebn.  d.  Physiol.,  9,  147-158,  1910;  J.  Wohlgemuth,  Handb.  d. 
Biochem.,  3',  180-181,  1910;  C.  Oppenheimer,  Die  Fermente,  3d  ed.,  pp.  242- 
252,  1910. 


IS  AUTOLYSIS  AN  INTRA- VITAL  PROCESS?  79 

son  of  various  organs  Vernon  found  the  duodenal  mucous 
membrane  richest  in  erepsin,  that  of  the  lower  portions  of 
the  intestine  poor  in  erepsin ;  of  the  other  organs  the  kidney 
showed  the  highest  content  of  ferment. 

It  can  be  readily  appreciated  that  there  is  difficulty  in 
attempting  to  deal  with  all  of  the  observations  upon  autolysis 
as  it  were  under  one  heading,  because  of  the  extreme  com- 
plexity of  the  chemical  processes  concerned.  It  may  be  re- 
garded as  a  step  in  advance  that  R.  L.  Benson  and  H.  G. 
Wells 6  have  perfected  a  physico-chemical  method  of  follow- 
ing continuously  the  course  of  autolysis  by  determining  the 
freezing-point  and  electrical  conductivity  of  the  autolysate, 
in  place  of  depending  exclusively  upon  the  increment  of 
incoagulable  nitrogen  or  the  disappearance  of  the  biuret 
reaction. 

The  whole  idea  of  the  physiological  significance  of  the 
autolytic  ferments  is  in  close  relation  with  the  proposition 
that  increase  in  the  "physiological  activity"  of  an  organ 
is  somehow  related  with  increase  of  its  intrinsic  autolytic 
capacity.  Accepting  provisionally  the  correctness  of  such 
a  statement,  if  we  endeavor  to  satisfy  ourselves  as  to  the 
actual  basis  thereof,  it  is  astonishing  to  find  upon  how  little 
foundation  of  fact  it  rests.  A  few  observations  from  Hof- 
meister's  laboratory  bear  upon  the  subject.  That  autolysis 
in  the  tissues  of  children  of  low  vitality  proceeds  more  slowly 
(measured  by  increase  of  incoagulable  nitrogen)  than  in 
those  of  normal  individuals,7  and  that  the  autolytic  activity 
of  a  functionating  mammary  gland  is  higher  than  of  a  rest- 
ing gland 8  (cf.  Vol.  I  of  this  series,  p.  361,  Chemistry  of  the 
Tissues)  should  be  mentioned;  and  in  addition  a  few  of 
Vernon's  observations9  are  applicable.  According  to  this 
author  the  average  quantity  of  "erepsin"  in  a  tissue  is  prac- 

6  R.  L.  Benson  and  H.  G.  Wells,  Journ.  of  Biol.  Chem.,  S,  61,  1910. 
TE.  Schlesinger   (F.  Hofmeisters  Lab.),  Hofmeister's  Beitr.,  Jh  87,  1903. 
8  P.  Hildebrandt  (F.  Hofmeister's  Lab.),  Hofmeister's  Beitr.,  5,  463,  1904. 
•1.  c. 


80  TISSUE  FERMENTS 

tically  constant  and  virtually  independent  of  diet ;  neverthe- 
less it  varies  with  the  state  of  functional  activity  of  the 
tissue.  In  fetal  tissues  it  is  at  minimum,  but  the  amount 
of  erepsin  rapidly  increases  as  development  proceeds,  reach- 
ing the  maximum  soon  after  birth.  It  is  asserted,  too,  that 
the  increased  protein  destruction  which  is  brought  about  by 
excessive  thyroid  substance  entering  the  system  is  also  mani- 
fested by  increase  of  post-mortem  autolysis  10 ;  although 
these  statements  have  been  opposed.  Addition  of  thyroid 
material  has  not  been  found  to  directly  increase  autolysis 
(consult  Vol.  I  of  this  series,  p.  450,  Chemistry  of  the 
Tissues ) .  It  has  been  found  that  autolysis  is  decidedly  more 
active  in  case  of  animals  which  have  fasted  before  death 
than  in  those  that  were  well  nourished.11  It  is  possible  to 
interpret  this  as  a  continuation  of  the  tissue  destruction 
which  is  going  on  in  marked  degree  in  fasting ;  but  one  might 
on  the  other  hand  be  justified  in  assuming  just  the  opposite, 
namely,  that  the  " functional  activity"  of  the  tissues  is 
lowered  in  states  of  fasting  while  their  digestive  ability  is 
increased,  in  line  with  the  fall  in  quantity  of  erepsin  in  the 
tissues  of  hibernating  animals  and  persons  reduced  by 
disease  which  Vernon  very  satisfactorily  demonstrated.12 
A  number  of  objections  have  been  presented  against 
regarding  autolysis  as  a  physiological  or  vital  process.  It  is 
said  that  autolysis  cannot  possibly  be  a  direct  continuation  of 
a  vital  process  because  it  does  not  appear  immediately  when 
death  occurs,  but  after  a  period  of  latency  of  several  hours.13 
Then,  too,  the  predilection  of  the  autolytic  ferments  for  an 
acid  reaction  has  been  made  an  objection 14 ;  (although  this 
is  answered  by  the  fact  that  even  with  the  natural  reaction 

10  Cf.  G.  Bayer    (M.  Löwit's  Lab.,  Innsbruck),  Sitzungsbericht  d.  Wiener 
Akad.,  US'",  181,  1909. 

11  J.  E.  Lane-Claypon  and  S.  B.  Schryver,  Journ.  of  Physiol.,  81,  169,  1904. 

12  H.  M.  Vernon,  Journ.  of  Physiol.,  33,  81,  1905. 

13  Lane-Claypon  and  Schryver,  1.  c. 

14  H.  Wiener  (J.  Pohl's  Lab.,  Prague),  Centralbl.  f.  Physiol.,  19,  349,  1905. 


DEAMIDIZING  TISSUE  FERMENTS  81 

of  the  blood  and  tissue-fluids  autolytic  processes  can  pro- 
ceed 15).  In  a  study  carried  out  in  the  laboratory  of  Julius 
Pohl 16  it  has  been  shown  that  allantoin,  which  appears  in 
large  amounts  in  autolysis  of  dog's  liver  17  and  for  which 
there  is  no  reduction  capacity  on  the  part  of  the  canine 
economy,  appears  nevertheless  in  but  very  small  amounts 
among  the  normal  excretory  products.  (Of  course,  if 
autolysis  were  actually  a  complete  duplicate  of  intravital 
changes,  we  would  necessarily  expect  that  allantoin  would 
normally  be  excreted  as  a  product;  yet  autolysis  might 
well  be  only  one  part  of  a  vital  process  and  it  might  well  be 
that  in  conditions  where  the  other  components,  particularly 
the  vital  oxidations,  are  absent  it  would  not  necessarily  give 
rise  to  exactly  the  same  end-products  as  found  in  life.)  To 
the  persistent  question  of  exactly  why,  if  autolysis  actually 
occurs  in  the  living  body  the  living  cells  are  not  digested, 
here  again  we  have  presented,  one  after  the  other,  anti- 
ferments,  the  immune  bodies  of  the  serum,  the  alkaline  con- 
ditions, etc.,  in  short  the  whole  arsenal  of  problematic 
hypotheses  with  which,  as  the  author  has  previously  in- 
sisted, we  are  in  the  vain  habit  of  trying  to  conceal  our 
ignorance  of  the  exact  reason  why  the  stomach,  intestine  and 
pancreas  are  prevented  from  digesting  themselves. 

Deamidizing  Tissue  Ferments. — The  atmosphere  sur- 
rounding this  subject  is  rather  unattractive  and  obscure, 
making  it  a  field  to  which  the  author  is  glad  to  devote  no 
more  time  than  is  actually  necessary.  Before  proceeding  to 
better  understood  matters,  however,  he  wishes  at  least  briefly 
to  refer  to  the  deamidizing  ferments.  As  originally  observed 
by  Martin  Jacoby  18  in  Hofmeister 's  laboratory,  in  the  course 

15  J.  Baer  and  A.  Loeb,  Arch.  f.  exper.  Pathol.,  53,  1,  1905;  A.  v.  Drjewecki, 
Biochem.  Zeitschr.,  1,  229,  1906;  Preti,  Zeitschr.  f.  physiol.  Cliem.,  52,  485, 
1907. 

16 R.  Poduschka  (Pohl's  Lab.,  Prague),  Arch.  f.  exper.  Path.,  4>f,  59,  1900. 

17  Borrissow  (Baumann's  Lab.),  Zeitschr.  f.  physiol.  Chem.,  19,  499  (1904). 

WM.  Jacoby  (F.  Hofraeister's  Lab.,  Strassburg),  Zeitschr.  f.  physiol.  Chem., 
30,  149,  1900. 
6 


82  TISSUE  FERMENTS 

of  autolytic  cleavage  of  tissue  proteids  there  occurs  a  much 
more  marked  production  of  ammonia  (presumably  from  the 
non-fixed  nitrogen  which  is  split  off  as  ammonia  by  hy- 
drolysis) than  in  acid  hydrolysis.  Thereafter  Sigmund 
Lang  19  in  the  same  laboratory  determined  the  autolytic 
separation  of  ammonia  both  from  acid  amides  (as  asparagin, 
COOH— CH2— CH.NH2— C0NH2,  and  glutamin)  and  from 
aminoacids.  It  is  now  recognized  that  deamidization  of  the 
first  of  these  series  takes  place  very  readily  in  alkali- 
hydrolysis  according  to  the  schema :  E.CONH2  -f  H20  = 
R.COOH  +  NH3.  The  author  has  not  failed  to  obtain  this 
result  in  any  of  his  studies,  conducted  in  association  with 
M.  Friedmann,  in  quantitative  comparisons  of  autolytic 
asparagin  cleavage  in  various  animal  tissues.20  The  fre- 
quent occurrence  of  amide-cleaving  ferments  in  vegetable 
tissues,  which  are  rich  in  acid  amides,  has  been  fully  estab- 
lished by  a  number  of  investigators.21  Of  more  interest  than 
this  group  of  enzymes  are  the  deamidases ,  which  are  capable 
of  splitting  off  from  an  aminoacid  its  firmly  attached  nitro- 
gen, which  successfully  resists  the  cleaving  power  of  boiling 
fuming  hydrochloric  acid.  Just  as  yeasts  or  moulds 
can  split  ammonia  from  aminoacids  and  transform 
them   into   oxy-fatty   acids22    (according   to   the   schema: 

B.NH2  E.OHK 

|  +  H20  =  NH3  -f|  )   so    precisely  the    same 

COOH  COOH/         r  J 

changes  can  apparently  take  place  in  autolysis  of  animal 

tissues.23     Cohnheim  has  observed  a  demidization  of  this 

sort  in  the  passage  of  aminoacids  through  the  living  intes- 

19  S.  Lang  (F.  Hofmeister's  Lab.,  Strassburg),  Hofmeister's  Beiträge,  5, 
320,  1904. 

20  0.  v.  Fürth  and  M.  Friedmann,  Biochem.  Zeitschr.,  26,  435,  1910. 

21 K.  Shibata,  N.  Castoro,  H.  Pringsheim,  W.  Butkewitsch,  A.  Kiesel. 
Literature:    O.  v.  Fürth  and  M.  Friedmann,  1.  c. 

22  H.  Pringsheim,  Biochem.  Zeitschr.,  12,  15,  1908. 

23  S.  Lang,  1.  c,  O.  Schumm,  Hofmeister's  Beitr.,  7,  175,  1906;  F.  Simon 
(Salkowski's  Lab.),  Zeitschr.  f.  physiol.  Chem.,  70,  65,  1910;  W.  Lindemann 
(Physiol.  Instit.,  Halle),  Zeitschr.  f.  Biol.,  55,  36,  1910. 


IMPORTANCE  OF  AUTOLYSIS  83 

tinal  wall  of  fishes  in  the  course  of  resorption; 24  which  calls 
to  mind  the  oft-repeated  statement  as  to  the  excessive  pres- 
ence of  ammonia  in  the  portal  blood  as  it  leaves  the  in- 
testinal wall.  The  author  sometimes  noted  in  the  course 
of  the  above  mentioned  autolytic  experiments  an  amount  of 
ammonia  obtained  from  asparagin  by  autolytic  cleavage 
with  intestinal  mucous  membrane,  so  large  that  it  surely 
represented  more  than  the  loose  amido-nitrogen  present  and 
probably  was  in  part  derived  from  cleavage  of  the  closely- 
combined  nitrogen  of  the  aminoacid.  The  author  acknowl- 
edges, however,  on  further  consideration  that  perhaps,  in 
spite  of  every  ordinary  precaution,  microorganisms  may 
have  played  some  part — a  thought  which  materially  disturbs 
his  satisfaction  in  this  as  well  as  in  other  similar  results. 
Importance  of  Autolysis  in  Various  Pathological 
Processes. — It  must  be  accepted,  therefore,  that  the  impor- 
tance of  autolysis  in  physiological  processes  is  by  no  means 
satisfactorily  established.  With  feelings  of  grateful  satisfac- 
tion akin  to  those  of  the  traveler  who  after  the  discomfort  of 
a  boggy  moor  finds  firmer  foothold  again  beneath  his  feet, 
we  approach  the  question  of  the  significance  of  autolysis  in 
pathology.  An  important  example  of  an  autolytic  process 
taking  place  in  the  living  body  has  come  to  be  recognized 
through  Martin  Jacoby's  studies  of  the  condition  of  the 
liver  in  phosphorus  poisoning,25  and  very  probably,  too,  in 
acute  yellow  atrophy  of  the  liver  which  is  very  similar  in 
its  manifestations  to  phosphorus  poisoning.26  In  both 
processes  an  impression  is  given  that  some  toxic  agent  has 
impaired  the  vitality  of  the  hepatic  cells,  and  that  the  auto- 

**0.  Cohnkeim  and  F.  Makita  (Heidelberg),  Zeitscbr.  f.  physiol.  Chem., 
61,  189,  1909;  0.  Cohnheim,  Sitzungsber.  d.  Heidelberger  Akad.  d.  Wiss.,  matb.- 
naturw.  Klasse,  1911,  30  Abh. 

26  M.  Jacoby,  Zeitschr.  f.  physiol.  Chem.,  SO,  174,  1900;  O.  Porges  and 
Przibram,  Arch.  f.  exper.  Patbol.,  59,  20,  1908. 

28  C.  Neuberg  and  P.  F.  Richter,  Deutsche  med.  Wochenschr.,  1904,  No.  14; 
A.  E.  Taylor,  Journ.  Med.  Research,  8,  424,  1902;  Zeitschr.  f.  physiol.  Chem., 
84,  580,  1902;  H.  G.  Wells,  Journ.  of  Exper.  Med.  9,  627,  1907. 


84  TISSUE  FERMENTS 

lytic  ferments  thereafter  are  free  to  "complete  the  burial" 
(cf.  Vol.  I  of  this  series,  p.  558,  Chemistry  of  the  Tissues). 
Apparently  the  proteins  in  the  course  of  the  process  become 
impoverished  in  their  basic  fractions  27  (especially  in  argi- 
nin),  presumably  because  the  basic  moiety  being  a  relatively 
instable  component  is  rather  readily  lost  in  the  catabolism  of 
the  protein  molecule.28  As  the  dissociation  advances  the 
final  cleavage  products,  the  aminoacids,  are  found  in  such 
quantity  in  the  circulation  that  their  presence  in  the  blood 
and  elimination  in  the  urine  become  striking.  In  the 
course  of  these  changes  the  exaggerated  autolysis  is  by  no 
means  limited  to  the  liver,  although  in  the  latter  it  is  most 
manifest.  Hsemic  alterations  in  phosphorus  poisoning, 
such  as  the  loss  of  fibrinogen  and  of  coagulability,  have  also 
been  referred  to  autolytic  changes.  P.  Saxl,  in  the  Vienna 
Physiological  Institute,  has  shown  that  even  if  dead  tissues 
are  treated  with  yellow  phosphorus  their  autolysis  is  in- 
creased and  the  appearance  of  cellular  "  fatty  degeneration" 
is  induced,  the  fat  present  in  the  constitution  of  the  cells 
becoming  histologically  visible.29 

Besides  phosphorus  there  are  undoubtedly  many  other 
toxic  agents  capable  of  increasing  autolysis.  Thus  H.  Gr. 
Wells 30  recognized  extensive  autolytic  changes  in  the  liver 
of  a  man  dead  from  chloroform  poisoning;  a  fact  explicable 
from  a  study  made  in  the  laboratory  of  H.  H.  Meyer31  indi- 
cating that  a  great  number  of  narcotic  substances,  either  in 
liquid  or  in  gaseous  form,  are  capable  of  hastening  and 
increasing  tissue  autolysis.     Apparently  this  is  dependent 

27  A.  Kossel,  Berliner  klin.  Wochenschr.,  190.'t,  1065 ;  A.  J.  Wakeman 
(Labor,  of  Kossel,  Heidelberg,  and  of  Herter,  New  York) ,  Journ.  of  Exper.  Med., 
7,  292  (1905)  ;   H.  G.  Wells,  1.  c. 

28  J.  Wohlgemuth,  Biochem.  Zeitschr.,  1,  161,  1906. 

29  P.  S'axl,  Hofmeister's  Beitr.,  10,  447,  1907  (under  direction  of  O.  v.  Fürth 
in  Physiol.  Instit.,  Univ.  of  Vienna). 

30  H.  G.  Wells  (Chicago),  Journ.  of  Biol.  Chem.,  5,  129,  1909. 

81 R.  Chiari  (H.  H.  Meyer's  Lab.,  Vienna),  Arch.  f.  exper.  Pathol.,  60, 
255,  1909. 


AUTOLYSIS  AND  THE  REGRESSIVE  CHANGES        85 

upon  the  lipoid-solvent  ability  of  such  substances  which 
causes  extensive  changes  in  the  intrinsic  permeability  of  the 
cellular  protoplasm.  Another  observation  which  should  be 
noted  in  the  same  connection  is  that  of  L.  Hess  and  P.  Saxl 32 
that  tissue  autolysis  is  apparently  increased  by  the  addition 
of  diphtheria  toxin,  tetanus  toxin  and  also  of  tuberculin 
(after  a  period  of  inhibition) ;  from  which  these  authors  are 
disposed  to  suggest  that  toxines  exert  an  influence  toward 
protein  cleavage.  Further  prosecution  of  similar  studies  is 
very  desirable  in  order  to  determine  to  what  extent  the  re- 
sults are  due  directly  to  the  toxines  and  not  to  other 
coincident  circumstances. 

Autolysis  and  the  Regressive  Changes  in  the  Living 
Body. — The  above  is,  however,  by  no  means  the  only  bearing 
of  autolysis  upon  pathological  processes.  Its  importance  in 
the  liquefaction  and  resorption  of  pneumonic  exudates  was 
recognized  by  Friedrich  v.  Müller  and  by  0.  Simon 33 ;  and 
there  can  be  but  little  error  in  assuming  that  autolysis  plays 
an  important  part  generally  wherever  tissue  structures, 
cellularized  exudates,  tumors,  fibrinous  clots,  tissue  grafts, 
etc.,  are  resorbed  in  the  living  body.  The  author  has  had 
occasion  (Vol.  I  of  this  series,  p.  370,  Chemistry  of  the 
Tissues)  to  point  out  that  it  is  reasonable  to  believe  that 
autodigestion  likewise  takes  part  in  such  physiological 
regressive  processes  as  the  involution  of  the  uterus  after 
delivery.  The  whole  subject  has  such  extensive  practical 
bearing  that  it  is  really  astonishing  how  little  is  actually 
known  with  reference  to  it. 

If  autolytic  processes  occur  thus  widely  in  the  living 
body  it  may  naturally  be  expected  that  the  system  may  be 
flooded  with  the  products  of  autolytic  digestion.     From  this 

32 L.  Hess  and  P. v  S'axl  (v.  Noorden's  Clinic,  Vienna),  Wiener  klin. 
Wochenschr.,  21,  248,  1908;  cf.  also  A.  Barloceo,  Pathologica,  2,  195;  abstracted 
in  Jahresber.  f.  Tierchem.,  J,0,  887,  1910. 

33  F.  Müller,  Verh.  des  20.  Kong.  f.  innere  Med.,  1902,  192;  O.  Simon, 
Deutsch.  Arch.  f.  klin.  Med.,  70,  604,  1901. 


86  TISSUE  FERMENTS 

standpoint  it  is  not  without  interest  to  note  the  appearance 
in  the  urine  of  albumoses  after  liquefaction  of  pneumonic 
exudates,  in  connection  with  large  abscesses,  and  in  instances 
of  softening  of  tumors.  Eamond 34  observed  after  ligation 
of  the  circulation  in  the  hind  leg  of  a  rabbit  for  some  hours 
that  general  disturbances  follow  when  it  is  reestablished 
(dyspnoea,  rapid  pulse,  etc.),  perhaps  due  to  autolytic  prod- 
ucts which  have  gained  access  to  the  circulation.  It  seems 
quite  possible,  too,  that  "autointoxication"  following  the 
resorption  of  products  of  regressive  autolytic  changes  may 
be  an  important  factor  in  human  pathology  (to  mention  only 
the  common  term,  "resorption  fever") ;  although  it  is  true 
we  have  but  little  positive  knowledge  in  this  connection.  It 
would  not  be  hard  to  fancy,  for  instance,  that  the  system  is 
not  indifferent  to  the  influence  of  a  wave  of  cholin  and  certain 
of  its  conversion  products  (v.  Vol.  I  of  this  series,  p.  190, 
Chemistry  of  the  Tissues)  which  might  find  origin  in  auto- 
lytic cleavage  of  tissue  lecithids  (even  if  in  a  general  way 
we  know  that  the  digestion  products  of  the  latter  are  harm- 
less after  passing  through  the  intestinal  wall). 

Relation  to  Bacterial  Processes. — In  a  further  sense  auto- 
lytic processes  may  have  important  pathological  application 
in  the  fact  that  certain  bacterial  endotoxines,  as  those  of  the 
typhoid  and  cholera  organisms,  become  active  only  after 
being  set  free  by  destruction  of  the  bacteria  themselves.  It 
seems  very  likely  to  the  author  that  there  is  an  important 
meaning  in  the  antibacterial  and  antitoxic  influence  of  tissue 
autolysates  (for  example,  the  autolysate  of  lymph  glands  has 
a  detoxifying  influence  upon  tetanus  toxine),  as  observed 
first  in  Hofmeister 's  laboratory.35 

Proteolytic  Ferments  of  Leucocytic  Origin. — Within 
the  past  few  years  especial  attention  has  been  very 
properly  devoted  to  a  particular  kind  of  autolytic  fer- 

"F.  Ramond,  Jour,  de  Physiol.,  10,  1052,  1908. 

«Conradi,  Hofmeister's  Beitr.,  1,  193,  1901;    L.  Blum,  ibid.,  5,  142,  1904. 


PROTEOLYTIC  FERMENTS  87 

ments,  tlie  proteolytic  leucocyiio  enzymes,  and  their  relation 
to  suppuration.  The  way  the  tissues  break  down  in  these 
latter  processes  and  the  " eating"  influence  of  the  pus  upon 
the  surrounding  tissues,  striking  even  for  non-medical  peo- 
ple, is  sure  to  suggest  the  idea  of  an  association  of  fermenta- 
tive changes.  As  a  matter  of  fact,  in  a  suppurative  process 
the  digestive  ferments  of  the  leucocytes,  of  the  bacteria,  of 
the  blood  plasma,  and,  too,  those  of  the  disintegrating 
tissues,  may  all  take  part.36  The  importance  of  each  par- 
ticular factor  is  naturally  difficult  of  definition.  Some  would 
have  it  that  the  greater  tendency  of  a  staphylococcus  infec- 
tion (in  comparison  with  a  streptococcus  infection)  to 
produce  suppuration  is  due  to  a  lower  proteolytic  power  on 
the  part  of  the  latter  microorganisms.37  It  is  probably  quite 
correct  to  ascribe  to  the  white  blood  corpuscles  an  especially 
marked  digestive  power.  It  is  thought  that  in  this  respect 
the  polynuclear  leucocytes  are  more  important  than  the 
mononuclears;  and  that  the  lymphocytes  develop  scarcely 
any  proteolytic  power.38  According  to  Jochmann  and 
others  the  proportion  of  proteolytic  enzymes  in  tissues  and 
essential  body  fluids  depends  very  largely  upon  the  number 
of  leucocytes  present  in  them.  By  placing  the  tissues  of 
either  the  lymph  glands,  spleen,  bone-marow  or  the  blood  of 
myeloid  leukaemic  cases,  or  material  from  tuberculous  lymph 
nodes  with  mixed  infection,  or  staphylococcus  pus  in  the 
incubator  for  a  time  on  a  Loeffler's  plate,  their  diges- 
tive power  is  shown  by  delle-erosion  in  the  medium.  In 
contrast  the  tissue  of  normal  lymphatic  glands  and,  too,  of 
those   in  lymphatic  leukaemia,    and   unmixed   tuberculous 

38  H.  G.  Wells,  Chemical  Pathology,  p.  93,  1907. 

87  Knapp,  Zeitschr.  f.  Heilk.  (Chirurgie),  23,  236,  1902. 

^Literature  upon  Leucoproteases  and  Antileucoproteases:  C.  Oppen- 
heimer,  Die  Fermente,  3d  ed.,  pp.  216-221,  1910;  cf.  especially  the  works  of 
Opie  and  Barker,  Jochmann  and  Müller  and  their  associates  (Ziegler,  Locke- 
mann,  Kantarowitsch,  Kolaczek),  and  also  M.  Fiessinger  and  P.  L.  Marie, 
Journ.  de  Physiol.,  11,  613,  1909. 


88  TISSUE  FERMENTS 

caseous  material  are  said  to  be  inactive.  In  contrast 
to  the  typical  leucoprotease  which  is  active  in  weakly 
alkaline  solutions,  a  ferment  derived  from  the  mononuclear 
leucocytes,  active  in  acid  solutions,  has  been  described. 
Attempts  have  been  made  to  " isolate"  the  ferment  by 
precipitating  with  alcohol  the  autolysates  of  pus,  spleen, 
marrow,  etc.,  with  subsequent  solution  of  the  precipitate  in 
dilute  glycerine,  and  to  differentiate  it  from  trypsin.  Ex- 
periments have  been  made  to  '  *  quantitatively  estimate"  the 
proteolytic  leucocytic  ferment  by  separation  of  the  white 
blood  corpuscles  in  citrated  blood  by  centrifugation,  dis- 
solving them  in  water,  and  allowing  the  ferment  to  act  upon 
a  solution  of  casein,  the  loss  in  casein  thus  occasioned  being 
thereafter  determined  by  the  aid  of  a  specific  precipitin 
serum.39  There  is  little  need  to  call  attention  to  the  lack 
of  exactness  naturally  inherent  to  all  such  experiments. 

To  briefly  refer  to  the  matter  of  antileucoprot  eases :  were 
it  correct  to  hold  that  suppurative  destruction  of  tissue  is  due 
to  the  digestive  action  of  the  leucoproteases,  it  would  be 
entirely  logical  to  hope  to  overcome  suppuration  by  the  anti- 
ferment  of  leucoprotease  or  by  the  "normal  antiferment"  of 
the  blood  serum.  As  it  was  believed,  following  Jochmann, 
that  antileucoprotease  is  identical  or  at  least  very  similar  to 
antitrypsin,  attempts  have  been  made  to  deal  with  suppura- 
tions by  antitrypsin  treatment.40  The  author  has  already 
(Vol.  I  of  this  series,  p.  560,  Chemistry  of  the  Tissues) 
pointed  out  the  more  than  problematic  nature  of  ' '  antitryp- 
sin" and  has  not  been  impressed  with  the  idea  that  the 
practical  results  of  antitrypsin  treatment  have  been  brilliant 
enough  to  set  aside  all  theoretical  doubt. 

Effect  of  Extrinsic  Factors  Upon  Autolysis. — Although 
the  effort  to  influence  autolysis  within  the  living  body  has 

88  M.  Franke  (Lemberg),  Wiener  klin.  Wochenschr.,  1910,  No.  33. 
40  Cf.  Jochmann  and  W.  Bätzner,  München,  med.  Wochenschr.,  1908,  2473 ; 
R.  Chiarolanza,  Med.  Naturw.  Arch.,  2,  No.  1,  1909. 


EFFECT  OF  EXTRINSIC  FACTORS  89 

had,  even  in  the  treatment  of  abscesses,  no  dazzling  results, 
studies  upon  the  influence  exerted  by  extrinsic  factors  upon 
autolysis  are  full  of  practical  interest  in  view  of  the  unques- 
tionable importance  the  process  has  in  every  question  of 
tissue  resorption  (v.  supra).  Only  the  most  interesting 
references  will  be  briefly  made  here  from  a  rich  literature 
bearing  upon  the  subject.41 

It  is  known  from  experiment  that  autolysis,  which  can 
set  in  at  the  natural  reaction  of  the  animal  juices,  is  very 
notably  increased  by  addition  of  small  amounts  of  acid,  even 
of  so  weak  an  acid  as  carbonic  acid.42  From  this  it  may  be 
concluded  that  autolysis  is  relatively  dependent  upon  the  in- 
tra-vital  and  postmortem  proportion  of  acid  in  the  tissues ; 
that,  for  instance,  the  insignificance  of  autolysis  in  em- 
bryonal tissues  is  perhaps  due  to  the  low  power  of  these  tis- 
sues to  form  acid.43  The  idea  has  been  suggested  that  the 
increased  tissue-protein  destruction  seen  in  the  asphyxias 
may  have  some  connection  with  an  increased  autolysis  made 
possible  by  the  increased  carbonic  acid  present  under  such 
circumstances.44  As  blood  serum 45  exerts  an  inhibitory  in- 
fluence upon  autolysis  (which  is,  however,  in  no  wise  specific, 
and  inheres  moreover  to  other  colloids,  as  egg-albumin  and 
gelatin46)  it  may  be  supposed  that  this  factor  may  be 
involved  in  a  regulative  way  over  catabolism  of  the  tissue 
proteins.  It  should  not  be  forgotten,  however,  that  the  rela- 
tion supposed  to  exist  between  the  latter  and  autolysis  is 
at  least  for  the  present  entirely  hypothetical. 

41  Literature  upon  Effect  of  Extrinsic  Factors  upon  Autolysis:  C.  Oppen- 
heimer,  Die  Fermente,  3d  ed.,  pp.  245-246,  1910. 

**  S.  Arinkin  (Salkowski's  Lab.,  Berlin),  Zeitsclir.  f.  physiol.  Chem.,  53, 
192,  1907;    S.  Yoshimoto,  ibid.,  58,  341,  1909. 

43  L.  B.  Mendel  and  C.  S.  Leavenworth,  Amer.  Journ.  of  Physiol.,  21, 
69,  1908. 

44  L.  Bellazzi  (Ascoli's  Lab.,  Pavia),  Zeitschr.  f.  physiol.  Chem.,  57,  389, 
1908. 

48  J.  Baer,  Arch.  f.  exper.  Pathol.,  56,  68,  1906. 

46  W.  T.  Longcope,  Journ.  of  Medical  Research,  18,  45,  1908. 


90  TISSUE  FERMENTS 

In  addition  to  the  above  it  has  been  discovered  that  the 
alkaline  earths  as  well  as  phosphorus,  as  above  stated,  hasten 
autolysis 47 ;  arsenic,48  quinine 49  and  quite  a  number  of 
other  drugs  manifest,  at  least  when  present  in  considerable 
quantities,  an  inhibitory  influence.  Many  drugs  seem  to 
accelerate  in  very  small  dosage,  but  to  inhibit  when  in  higher 
proportions. 

The  influence  of  colloidal  metals  50  in  stimulating  auto- 
lysis, made  known  by  observations  of  Ascoli  in  Pavia  and 
his  associates,  seems  to  the  author  worthy  of  much  con- 
sideration. Eecently  a  contribution  by  C.  Neuberg  and 
Caspari  has  attracted  considerable  attention,  dealing  with 
the  results  obtained  in  treating  mouse  cancers  with  colloids 
of  the  heavy  metals.  A  very  rapid  softening  and  liquefac- 
tion of  the  tumors  was  produced,  and  in  a  number  of  cases 
actual  tumor  destruction  was  attained,  apparently  without 
danger  to  the  life  of  the  experiment  animals  (v.  Vol.  I  of  this 
series,  p.  555  ff,  Chemistry  of  the  Tissues).  One  cannot  but 
hesitate  to  spoil  the  pleasure  this  fine  result  inspires  by 
stating  the  fact  that  mouse  cancers  are  incomparably  more 
benign  than  the  analogous  tumors  of  man  (a  point  which 
Wassermann  explicitly  brings  out  in  warning  against  em- 
ploying the  method  in  human  therapy,  in  an  article  announc- 
ing a  similar  result  attained  in  animals  by  the  use  of  selenium 
preparations). 

There   is  food   for   further  thought   in   the   fact   that 

«L.  Launoy,  C.  R.  Soc.  de  Biol.,  62,  487,  1907;  L.  Brüll  (V.  Noorden's 
Clinic,  Vienna),  Biochem.  Zeitschr.,  29,  408,  1910. 

48  L.  Hess  and  P.  Saxl,  Zeitschr.  f.  exper.  Pathol.,  5,  89,  1908. 

*°  E.  Laqueur,  Arch.  f.  exper.  Pathol.,  55,  240,  1906;  cf.  also  Biochem. 
Centralbl.,  8,  564,  1909;  Centralbl.  f.  Physiol.,  22,  717,  1909;  G.  Izar  (Ascoli's 
Lab.,  Pavia),  Biochem.  Zeitschr.,  21,  46,  1909. 

60  M.  Ascoli  and  C.  Izar,  Biochem.  Zeitschr.,  6,  192,  1907;  7,  142,  1907;  10, 
356,  1908;  H,  491,  1908;  17,  361,  1909;  L.  Preti,  Zeitschr.  f.  physiol.  Chem., 
58,  539,  1909;  60,  317,  1909;  G.  Izar,  Biochem.  Zeitschr.,  22,  371,  1909;  M. 
Truffi,  ibid.,  23,  270,  1910,  and  earlier  publications  from  the  same  laboratory. 


PROTEOLYTIC  TISSUE  FERMENTS  91 

besides  radium,51  consideration  of  which  in  the  treatment 
of  tumors  has  been  given  in  an  earlier  lecture  (v.  Vol.  I  of 
this  series,  pp.  557-558,  The  Chemistry  of  the  Tissues),  two 
other  great  blessings  to  man,  mercury  and  iodine,  are  to  be 
numbered  among  the  agents  capable  of  increasing  autolysis. 
While  the  addition  of  iodide  of  potassium  to  an  autolysing 
mass  is  without  effect,  a  very  decided  increase  of  hepatic 
autolysis  has  been  attained  in  animals  by  long  preadminis- 
tration  of  the  salts  of  iodine.52  May  it  not  be  that  the  favor- 
able influence,  confirmed  in  hundreds  of  thousands  of  cases, 
which  this  agent  exerts  upon  luetic  processes,  is  in  some 
way  connected  with  stimulation  of  autolysis?  The  feW 
observations  here  referred  to  give  us,  of  course,  no  justifica- 
tion for  such  a  conclusion.  But  as  a  pointer  for  continued 
investigation  they  deserve  constant  reflection. 

Abderhalden 's  Investigations  Upon  Proteolytic  Tissue 
Ferments. — We  are  indebted  for  very  real  progress  in  the 
study  of  proteolytic  tissue  ferments  to  the  extensive  investi- 
gations of  Emil  Abderhalden  and  his  army  of  collaborators.53 
By  his  method  of  work,  testing  the  tissue  enzymes,  not  as  was 
always  done  before  upon  indefinable  proteins,  but  upon 
numerous  well-defined  Polypeptids,  Abderhalden,  it  may  be 
said,  dragged  the  whole  problem  from  the  depth  of  a  dismal 
cloud-mass  into  an  enlightened  level;  and  it  is  not  a  diffi- 
cult thing  to  prophesy  that  when  this  series  of  studies  has 

61  J.  Wohlgemuth,  Berliner  klin.  Wochenschr.,  1904,  No.  26,  704;  S. 
Löwenthal  and  E.  Edelstein,  Biochem.  Zeitschr.,  14,  484,  1908. 

62  L.  Kepinow  (Instit.  for  Cancer  Investigation,  Heidelberg),  Biochem. 
Zeitschr.,  37,  238,  1911;  L.  B.  Stookey,  Proc.  Soc.  Exp.  Biol.,  5,  89;  abst.  in 
Jahresb.  f.  Tierchem.,  88,  842,  1908. 

83  E.  Abderhalden,  in  association  with  C.  Brahm,  H.  Deetjen,  A.  Gigon,  M. 
Guggenheim,  A.  Hunter,  K.  B.  Immisch,  A.  Israel,  E.  Kämpf,  A.  H.  Koelker,  W. 
Manwaring,  J.  S.  McLester,  F.  Lussana,  L.  Pinkussohn,  A.  Pringsheim,  B.  Opp- 
ler,  A.  Rilliet,  P.  Rona,  B.  Schilling,  A.  Schittenhelm,  J.  G.  Sleiswyk,  E.  Stein- 
beck, J.  Teruuchi,  L.  Wacker,  W.  Weichhardt.  Literature:  E.  Abderhalden, 
Lehrb.  d.  physiol.  Chem.,  2d  ed.,  pp.  266-268,  1909;  and  Synthese  der  Zellbau- 
steine in  Pflanze  und  Tier,  p.  119,  Berlin,  J.  Springer,  1912 ;  C.  Oppenheimer,  Die 
Fermente,  3d  ed.,  pp.  172-176,  1910. 


92  TISSUE  FERMENTS 

reached  a  definite  conclusion  many  fundamental  problems 
of  physiology  and  of  pathology  will  be  regarded  very 
differently  than  is  now  possible. 

Detection  of  Proteolytic  Tissue  Ferments,  by  Employing 
Glycylty rosin,  Silk-peptone  and  Glycyltryptophane. — Men- 
tion may  first  be  made  of  some  part  at  least  of  the 
progress  in  technique  contributed  by  Abderhalden  in  this 
field.  A  useful  method  of  determining  peptolytic  tissue  fer- 
ments is  based  upon  their  action  on  a  solution  of  some  Poly- 
peptid, which,  like  glycyltyrosin  or  a  given  silk-peptone, 
contains  a  relatively  insoluble  aminoacid.  The  ferment 
solution  to  be  tested  or  a  section  of  an  organ  is  put  in  a  25 
per  cent,  solution  of  silk-peptone  and  placed  in  the  incubator 
after  toluol  has  been  added ;  after  a  few  hours  presence  of 
the  ferment  manifests  itself  by  the  separation  of  tyrosin. 
The  tyrosin  is  to  be  found  limited  to  the  cortical  surface  of 
sections  of  renal  tissue,  for  example,  the  medulla  remaining 
free;  in  fatty  kidneys  the  tyrosin  separation  is  distinctly 
decreased.  It  is  equally  simple  to  determine  the  presence  of 
peptolytic  ferments  in  sections  of  vegetable  material.  An- 
other process  which  is  also  available  for  microchemical  work 
is  based  upon  the  fact  that  a  Polypeptid  containing  trypto- 
phane, as  glycyltryptophane,  when  treated  with  bromine 
water  will  yield  a  violet  color,  not  at  once,  but  after  the 
separation  of  the  tryptophane. 

Optical  Method. — The  " optical  method"  introduced  by 
Emil  Fischer  and  Abderhalden  has  yielded  excellent  results 
in  this  field;  the  author  has  previously  referred  to  this  (Vol. 
I  of  this  series,  p.  555,  Chemistry  of  the  Tissues,  and  in  the 
present  volume,  Chapter  II) .  This  method  demands  the  use 
of  a  suitably  sensitive  polarization  apparatus  with  which  to 
follow  and  accurately  determine  each  step  of  the  course  of 
cleavage  of  optically-active  Polypeptids  in  which  the  indi- 
vidual " building  stones"  are  loosened  from  their  structural 
positions  in  the  complexly  constructed  Polypeptid.    An  illus- 


OPTICAL  METHOD  93 

tration  may  serve  to  make  the  method  clear.54  The  tripeptid 
d-Alairyl-glycyl-glycin  shows  in  aqueous  solution  a  specific 
rotation  of  +  30°.  This  substance  can  give  rise  in  cleavage 
to  d-Alanyl  and  to  glycylglycin.  The  former  rotates  light 
but  -f-  2.4°,  and  the  latter  is  optically  inactive.  When  cleav- 
age occurs  therefore  there  is  a  sudden  decrease  in  the  rota- 
tive power.  Quite  a  different  result  is  seen,  however,  if  a 
cleavage  occurs  which  produces  giycocoll  and  d-alanylglycin. 
The  latter  of  these  two  substances  is  characterized  by  a  very 
high  rotative  power,  of  +  50°,  and  this  type  of  cleavage 
therefore  shows  itself  by  access  of  optical  rotation. 

Emil  Fischer  and  Abderhalden  made  the  important  state- 
ment that  racemic  Polypeptids  are  split  asymmetrically  by 

* 
proteolytic  ferments.     Examining  a  dipeptid,  NH2-CH.C0 

NH.CH.COOH,  ft  may  ^e  geen  there  are  ^vo  asymmetrically 

placed  carbon  atoms.  From  this  it  follows,  in  accordance 
with  the  well-known  principle  of  van't  Hoff,  there  exist  four 
isomers,  which  group  themselves  into  two  racemoid  bodies, 
thus : 

d-Alanyl-1-leucin  < — >  1-Alanyl-d-leucin  (racemic  body  A). 
d-Alanyl-d-leucin  < >  1-Alanyl-l-leucin  (racemic  body  B). 

It  has  developed  that  the  two  racemic  compounds  behave 
entirely  differently  toward  pancreatic  juice.  Only  that  one 
which  presents  the  combination  of  the  natural  aminoacids 
d-alanin  and  1-leucin — that  is,  racemic  body  A — is  split,  and 
this  is  attacked  asymmetrically  as  only  the  combination 
d-Alanyl-1-leucin  is  split ;  while  the  combination  of  1-Alanyl- 
d-leucin  remains  unchanged.  In  this  respect  the  proteolytic 
ferments  of  animal  tissues  are  shown  to  be  analogous  in  their 
influence  to  that  of  the  pancreatic  juice. 

&;  E.  Abderhalden,  Lehrb.  d.  physiol.  Chem.,  2d  ed.,  pp.  266,  626,  1910. 


94  TISSUE  FERMENTS 

Inhibition  of  Proteolytic  Processes  by  the  Products  of 
Protein  Cleavage. — It  has  long  been  known  that  the  action 
of  proteolytic  ferments  is  inhibited  by  the  presence  of  pro- 
tein cleavage  products.  It  has  been  repeatedly  shown  that 
the  inhibitive  influence  is  due  to  the  optically  active  amino- 
acids,  in  which  this  power  resides,  which  exist  in  the  proteins. 
It  is  suggested  in  explanation  that  these  aminoacids  (and 
only  these)  bind  the  ferment  and  thus  prevent  its  fixing  its 
object  of  prey,  the  protein  molecule.  This  is  merely  sug- 
gested because  the  test  tube  is  incapable  of  affording  a  true 
picture  of  the  proteolytic  processes  which  are  going  on  in 
the  living  body.  It  should  be  realized  that  in  the  living  body, 
whether  proteolysis  is  taking  place  in  the  digestive  canal  or 
in  the  tissues,  the  cleavage  products  of  protein  are  removed, 
as  they  are  formed,  from  further  contact  with  the  proteolytic 
enzyme,  and  thus  the  inhibition  inevitable  in  the  test  tube  is 
avoided. 

Moreover  a  natural  prolongation  of  proteolytic  cleavage 
may  be  conceived  from  the  fact  that  ceteris  paribus  the 
longer  molecular  chains  are  more  readily  preyed  upon  than 
short  ones;  with  equal  amounts  of  ferment  and  equal 
molecular  concentration  of  Polypeptids,  a  tetrapeptid  is  split 
more  quickly  than  a  tripeptid,  and  the  latter  in  turn  more 
quickly  than  a  dipeptid. 

Classification  of  Proteolytic  Ferments. — By  substitu- 
tion of  definite  Polypeptids  for  high-molecular  proteins  a 
basis  will  be  found  for  construction  of  a  rational  classi- 
fication and  differentiation  of  proteolytic  ferments.  We 
know  today,  for  example,  that  pepsin  is  incapable  of 
acting  upon  any  of  the  hitherto  demonstrated  Polypeptids ; 
that  trypsin  will  separate  some  of  them  but  by  no  means 
all;  while  erepsin  can  dissociate  even  those  Polypeptids 
which,  like  glycylglycin,  successfully  resist  trypsin.  Keep 
in  mind  that  every  cell  and  every  cellular  combination 
in  animals  and  plants,  from  infusorium  and  bacterium  up  to 


PEPTOLYTIC  POWER  OF  BLOOD  SERUM      95 

the  highly  differentiated  organs  of  man,  is  in  reality  a  chem- 
ical laboratory,  in  which  proteolysis  is  going  on  in  myriads 
of  different  forms !  Think  of  the  crudeness  of  our  attempts 
to  classify  all  these  heretofore !  Many  a  time  in  the  last  ten 
years  when  busily  engaged  in  collecting  material  for  a  com- 
parative chemical  physiology  of  the  lower  animals,  has  the 
author  lost  his  temper  on  seeing  how  learned  men,  in  endless 
controversy  as  to  whether  this  or  that  secretion  possess  a 
' '  peptic "  or ' '  tryptic ' '  character,  quarrel  among  themselves, 
without  the  least  thought  on  the  part  of  any  one  of  them 
of  some  better  trophy  than  that  of  their  trivial  "clearly 
reddened"  or  " distinctly  blued"  litmus  papers.  It  is  to  be 
hoped  that  as  the  methods  elaborated  by  Abderhalden  come 
into  general  appreciation  it  will  all  be  very  different.  It  is 
quite  likely  that  these  methods  will  not  be  as  easy  of  prose- 
cution as  litmus-paper  processes ;  and  it  is  to  be  expected, 
too,  that  facility  in  them  will  require  progressively  a  more 
and  more  comprehensive  chemical  training. 

Peptolytic  Poiver  of  Blood  Serum. — In  conclusion  refer- 
ence may  again  be  made  to  the  promise  held  out  by  the  recent 
methods  of  study,  of  information  regarding  the  active 
proteolytic  agencies  in  the  blood  serum.  Abderhalden  and 
his  collaborators  have  discovered  that  subcutaneous  or  in- 
travenous injection  of  specifically  foreign  but  not  of  specifi- 
cally homologous  protein  increases  the  peptolytic  capacity 
of  blood  serum.  The  normal  serum  of  a  dog,  for  example, 
is  incapable  of  catabolizing  silk-peptone.  Its  proteolytic 
ability  is  apparently  increased  by  parenteral  introduction  of 
horse  serum,  gliadin,  casein,  diphtheria  toxin,  tuberculin, 
but  not  by  dog  serum.  Serological  studies  in  this  line,  ap- 
plying the  optical  method,  are  full  of  suggestive  promise  for 
manjr  of  our  important  problems  (as  anaphylaxis).  It  is  a 
matter  of  regret  that  further  discussion  of  the  theme  cannot 
be  pursued ;  the  whole  subject  is  thus  far  too  undeveloped 
to  permit  a  definitive  conclusion. 


96  TISSUE  FERMENTS 

Mere  mention  can  be  given  a  very  interesting  practical 
application  of  the  optical  method,  that  of  its  employment  in 
the  diagnosis  of  pregnancy.  Abderhalden  started  out  with 
the  idea  that  if  it  be  correct,  as  many  gynecologists  testify, 
that  cellular  elements  of  the  chorionic  villi  pass  into  the  cir- 
culating blood  of  pregnant  females,  these  being  in  a  sense 
foreign  to  the  blood  should  increase  the  proteolytic  capacity 
of  the  blood  against  them.  Investigation  actually  corrobor- 
ated the  assumption,  it  being  possible  to  demonstrate  by 
optical  means  that  serum  from  gravid  females  has  the  power 
of  inducing  cleavage  of  a  placental  peptone  (obtained  by 
partial  hydrolysis  of  human  placental  tissue  by  sulphuric 
acid),  while  the  same  power  does  not  exist  in  the  serum  of 
normal,  non-gravid  individuals.  The  chemical  diagnosis  of 
pregnancy  can  be  made,  however,  in  much  simpler  manner, 
by  dialyzing  the  serum  of  the  pregnant  woman  in  which 
bits  of  boiled  placental  tissue  have  been  suspended  against 
water,  and  then  testing  the  dialysate  for  material  responding 
to  the  biuret  reaction.  At  the  present  time  Abderhalden  is 
still  engaged  in  so  far  perfecting  the  method  that  it  may  be 
adapted  to  the  requirements  of  medical  practice.55 

55  E.  Abderhalden  and  M.  Kiutsi,  Zeitschr.  f.  physiol  Chem.,  77,  249,  1912; 
E.  Abderhalden,  ibid.,  81,  90,  1912.  (Employment  of  triketohydrindenhydrate 
as  peptone  reagent.) 


CHAPTER  V 
UREA.    HIPPURIC  ACID.     EXCRETION  OF  AMINOACIDS 

UREA 

It  has  been  the  earnest  wish  of  the  author  to  present  in 
logical  sequence  as  fully  as  possible  the  world  of  biochemical 
fact  and  error;  but,  as  has  been  said  before,  and  that  not 
without  feelings  of  decided  rebellion,  at  a  single  stride  the 
darkly  yawning  chasm  of  intermediate  metabolism  must  be 
passed,  with  the  vast  number  of  unsolved  enigmas  it  harbors, 
and  attention  next  directed  to  the  end-products  of  protein 
metabolism. 

The  present  chapter  has  first  to  deal  with  urea,  the  most 
important  of  the  nitrogenous  end-products  of  mammalian 
metabolism.  What  do  we  know  of  the  method  and  manner 
of  urea- formation? 

Theories  of  the  Formation  of  Urea  in  the  Living  Body. — 
Of  the  many  theories  which  have  been  proposed  to  ex- 
plain the  origin  of  urea  there  are  today  practically,  in  the 
author's  opinion,  only  two  worthy  of  consideration,  that  of 
Schmiedeberg  and  that  of  Hofmeister.  The  former,  the 
"anhydride  theory,"  regards  urea  as  originating  from 
ammonium  carbonate  by  withdrawal  of  water : 

AMMONIUM   CARBONATE      AMMONIUM   CARBAMATE  UREA 

/0(NH4)  /NH2  /NH2 

CO  — >-      CO  — >■    CO 

\C(NH4)       — h2o  \0(NH4)     — h2o  \NH2. 

In  this  schema  the  carbamate  of  ammonium  may  be  regarded 
as  an  intermediate  product.  Hofmeister,  on  the  other  hand, 
in  his  theory  holds  that  urea  is  formed  by  an  oxy dative 
synthesis,  in  which  one  of  the  components  is  supposed  to  be 
an  NH2  "rest"  arising  from  oxidation  of  ammonia,  and  the 
other  an  NH2.CO  rest.  The  hydrocyanic  acid  theory  of 
Hoppe-Seyler,  which  for  decades  has  trailed  through  the 
7  97 


98  UREA.    HIPPURIC  ACID.    AMINOACIDS 

literature  of  the  subject,  may  to-day  be  consigned  finally  to 
well  deserved  rest.  There  was  a  time  when  it  was  entirely 
proper  to  think  it  possible  that  urea  may  be  formed  in  the 
body  precisely  as  in  Wohler's  synthesis  by  transformation 
from  ammonium  cyanate;  but  after  vainly  searching  for 
hydrocyanic  acid  for  a  number  of  decades  in  the  intermediate 
metabolism  the  theory  may  be  finally  dropped,  in  the 
author's  opinion,  from  current  consideration.  If  we  are  to 
drag  along  the  whole  dead  weight  of  wornout  mistakes  of 
former  generations  on  our  backs,  how  can  we  be  expected  to 
acquire  the  strength  and  vigor  required  for  the  grinding 
effort  to  reach  the  higher  levels  of  the  future? 

Ur  amino  acids. — The  formation  of  certain  conjugate 
products,  the  uraminoacids,  suggesting  the  possible  avail- 
ability of  free  CONH2  complexes,  may  be  regarded  as  favor- 
ing Hofmeister 's  theory.  Thus,  as  Salkowski  discovered, 
aminobenzoic  acid  and  sulphanilic  acid  introduced  into  the 
system,  as,  too,  taurin,  can  attach  CONH2  groups  to  them- 
selves ;  and  even  ingested  tyrosin  may  be  observed  linked 
with  such  a  complex  (cf.  Vol.  I  of  this  series,  p.  47,  Chemistry 
of  the  Tissues) : 

m  =  AMINOBENZOIC   ACID  SULPHANILIC  ACID 

/NH2  /NH.CO.NH2  /NH2  /NH.Co.NH2    ; 

C«ILj  — >CeH4  ;      C6H4         — >-C6-H4 

\COOH  \COOH  \HS03  \HSOs 

TAURIN 

CH2.NH2  CH2.NH.CO.NH2 

CH2HS03  "  CH2HSO, 

TYROSIN 

OH.CÄ— CH2  OH— CsH*— ch2 

I  I 

CH.NH2    — >  CH.NH.CO.NH2 

I  I 

COOH  COOH. 

But  it  has  been  proved  that  in  alkaline  reaction  aminoacids 
with  urea  are  very  readily  transformed  into  uraminoacids.1 

1F.  Lippich,  Ber.  d.  deutsch,  ehem.  Ges.,  39,  2953,  1906;  41,  2053,  2074, 
1908. 


MECHANISM  OF  VITAL  OXIDATION  99 

R.NH,  NH,\  R.NH.CO.NH, 

I  +  CO  =  NH3  +    I 

COOH  NH2/  COOH. 

It  is  sufficient,  for  example,  to  heat  an  alkaline  urine  contain- 
ing tyrosin  to  steaming  to  effect  such  a  transformation.2 
One  must  believe  therefore  that  we  are  no  longer  justified 
in  any  conclusions  bearing  upon  the  mechanism  of  urea 
formation  from  the  formation  of  these  conjugate  products. 
From  experiments  in  Hofmeister 's  laboratory3  it  was 
determined  that  by  perfusing  the  isolated  living  liver  with 
taurin  the  linking  of  CONH2,  as  above  suggested,  does  not 
directly  take  place;  this  group  becoming  available  only  if 
glycocoll  is  introduced  at  the  same  time.  The  CONH2  group 
at  all  events  appears  from  oxidation  of  the  latter ;  whether, 
however,  from  finished  urea  (as  in  the  formation  of  a 
uraminoacid  from  aminoacid  and  urea  in  the  laboratory)  or 
from  some  precursor  of  urea, 

CHj.NH,  CO.NH,  •  •  •  CO.NH, 

COOH  COOH  C02    , 

cannot  at  present  be  determined. 

Mechanism  of  Vital  Oxidation  of  Nitrogenous  Sub- 
stances.— Schmiedeberg 's  anhydride  theory  is  based  on  the 
assumption  that  protein  is  burned  in  the  living  body  to  its 
end-products,  all  the  carbon  eventually  becoming  C02,  all 
the  hydrogen  water,  the  nitrogen  appearing  as  ammonia, 
just  as  in  preparation  of  a  protein  for  Kjehldahl  determi- 
nation. 

At  present  the  great  riddle  of  the  vital  combustion  proc- 
esses, it  is  safe  to  say,  is  incomprehensible  to  us ;  and  it  is 
beyond  our  understanding  how  the  living  body  manages  at  a 
temperature  less  than  40°  C.  to  effect  an  oxidation  which  in 
the  laboratory  we  are  able  to  accomplish  only  by  great  heat 


2H'.  D.  Dakin,  Jour,  of  Biol.  Chem.,  8,  25,  1910. 

3  P.  Philosophow   (F.  Hofmeister'a  Lab.,  Strassburg),  Biochem.  Zeitschr., 
26,  131,  1910;  cf.  therein  Literature  upon  the  Uraminoacids. 


100  UREA.    HIPPURIC  ACID.    AMINOACIDS 

or  by  powerful  reagents  like  fuming  sulphuric  acid.  This  is 
one  of  life's  great  mysteries.  That  the  living  cell,  however, 
after  successfully  performing  the  trick  of  burning  protein 
into  C02,  H20  and  NH3,  can  finally  change  the  carbonate  of 
ammonium  into  urea  by  withdrawal  of  two  molecules  of 
water  (carbonate  of  ammonium  necessarily  resulting  from 
the  combination  of  the  carbonic  acid  with  ammonia  in  aque- 
ous solution),  is  apparently  much  less  inconceivable;  and 
from  this  stage  forward  it  is  rather  hard  to  comprehend 
why  Schmiedeburg 's  theory  should  present  any  particular 
difficulties.  Schmiedeburg 's  famous  pupil,  v.  Schroeder, 
whose  work  was  ended  by  his  premature  death,  was  able  to 
show  by  his  frequently-quoted  perfusion  experiments  that 
the  isolated  liver  is  able  to  transform  not  only  ammonium 
carbonate  but  also  the  ammonium  salts  of  organic  acids,  as 
formate  of  ammonium,  into  urea.  Thereafter  Salaskin  dem- 
onstrated that  aminoacids  are  liable  to  the  same  change. 
How  this  is  actually  accomplished  and  what  intermediate 
products  are  produced  are  entirely  unknown.  We  have  no 
knowledge,  for  example,  in  the  oxidation  of  glycocoll  whether 
the  oxygen  combines  first  with  the  carbon  or  with  the 
nitrogen,  and  whether  glyoxylic  acid  (occasionally  appear- 
ing in  metabolism)  is  an  intermediate  product : 4 

HYDROXYLAMINOACETIC   ACID  GLYOXYLIC   ACID 

/OH  COH 

CH.NH2        =  +NHj. 

COOH 


CH2.NH2        COOH 
I 
COOHI\     CH2.NH.OH 

COOH 
Ammonium  Carbamate. — As  previously  stated,  in  anhy- 
dration-production  of  urea  ammonium  carbamate,  Co/q ^H » 
may  appear  as  an  intermediate  material.     For  considerable 
time  this  compound,  occasionally  found  in  the  blood,  urine 

*H.  Eppinger  (Hofmeister's  Lab.,  Strasssburg),  Hofmeister's  Beitr.,  6,  481, 
1905. 


PLACE  OF  UREA  FORMATION  101 

and  tissues,  has  been  regarded  as  important  in  pathology, 
being  looked  upon  as  especially  toxic  and  as  responsible  for 
the  symptoms  of  intoxication  appearing  after  administra- 
tion of  meat  to  animals  with  Eck  fistulas.  The  import  and 
credibility  of  these  ideas  have  been  completely  lost,  however, 
since  it  has  been  shown  that  anywhere,  as  in  the  urine,  where 
an  ammonium  salt  in  aqueous  solution  comes  in  contact  with 
sodium  carbonate  ammonium  carbamate  is  produced,  the 
NH3  and  C02  being  distributed  proportionately  to  form 
ammonium  carbamate  and  ammonium  carbonate  in  con- 
nection with  the  disturbance  of  equilibrium  and  water 
transportation.5 

Place  of  Urea  Formation.  Exclusion  of  the  Liver.— 
In  literature  the  question  of  the  place  of  urea  formation 
occupies  a  very  disproportionate  amount  of  space.  That  a 
process  of  this  sort  actually  takes  place  in  the  liver  is  amply 
proved  by  v.  Schroeder  's  experiments ;  but  it  is  by  no  means 
settled  that  the  liver  is  the  sole  location  in  which  urea  is 
formed.  Efforts  have  been  made  to  come  to  some  conclu- 
sion upon  this  point  by  study  of  the  sequels  of  hepatic 
exclusion.  Experiments  along  this  line  of  inquiry  by  Nencki 
and  Pawlow  (with  Hahn  and  Massen)  in  which  they  made 
use  of  the  Eck  fistula  (cf.  Vol.  I  of  this  series,  p.  296,  Chem- 
istry of  the  Tissues),  have  become  famous.  Here,  too,  we 
may  class  the  experiments  in  Hofmeister 's  laboratory  in 
which  the  liver  is  destroyed  by  injection  of  acid  into  the 
biliary  duct,  and  by  ligation  of  the  hepatic  vessels.  In  addi- 
tion a  number  of  observations  upon  nitrogen  elimination  in 
acute  yellow  atrophy,  phosphorus  poisoning  and  hepatic 
cirrhosis  are  of  significance.6      The  conclusion  from  this 

5  J.  J.  Macleod  and  H.  D.  Haskins  (Cleveland),  Jour,  of  Biol.  (Jhem.,  1, 
319,  1905. 

8  Literature  upon  Formation  of  Urea  in  the  Living  Body  and  its  Relation 
to  Defect  of  Hepatic  Function:  M.  Jacoby,  Ergebn.  d.  Physiol.,  1,  532,  1902; 
A.  Magnus-Levy,  Noorden's  Handb.  d.  Pathol,  d.  Stoffw.,  1,  99-117,  1906; 
E.  Weinland,  Nagel's  Handb.  d.  Physiol.,  2,  481,  1907;  J.  Wohlgemuth,  Handb. 
d.  Biochem.,  3',  183,  1910;   A.  Ellinger,  ibid.,  S',  563,  1910. 


102  UREA.    HIPPURIC  ACID.    AMINOACIDS 

whole  group  of  studies  may  be  briefly  condensed  into  the 
statement,  that  the  liver  can  be  practically  excluded 
without  abolishing  or  in  any  marked  degree  reducing  the 
formation  of  urea.  It  is  true  that  in  these  subjects 
there  sometimes  occurs  a  lowering  of  the  urea  (from  90  to 
75  per  cent,  of  the  total  nitrogen),  with  corresponding  in- 
crease of  ammonia  (the  latter  increasing  from  about  3  to  5 
per  cent,  of  the  total  nitrogen  to  20  per  cent,  or  more).  But 
on  the  other  hand  it  is  known  that  loss  of  hepatic  function 
coincides  frequently  with  an  "  acidosis,"  that  is,  with  ac- 
cumulation of  acid  metabolites ;  and  it  is  not  at  all  unreason- 
able to  think  that  this  may  very  satisfactorily  explain  the 
diminution  of  urea  formation  and  coincident  ammonia  in- 
crease (v.  inf.).  In  dog  fish,  in  the  tissues  of  which  there  is 
an  unusually  large  proportion  of  urea,  it  has  not  been  pos- 
sible to  reduce  this  by  extirpation  of  the  liver.7  Recent  clin- 
ical observations  have  invariably  indicated  that  ammonia 
elimination  is  very  commonly  heightened  in  severe  liver 
affections,  although  scarcely  more  than  in  fever  or  in  con- 
ditions of  acidosis ;  and  it  is  altogether  impossible  to  con- 
clude that  observation  of  urea-ammonia-elimination  affords 
a  safe  basis  or  deduction  as  to  the  hepatic  function.8 

Generally  speaking,  the  inclination  at  the  present  time 
is  increasingly  toward  the  belief  that  the  ability  to  form 
urea  is  by  no  means  confined  to  the  liver,  but  is  one  of  the 
common  characteristics  of  all  living  cells,  just  as  is  the 
power  of  protein  combustion.  In  very  low  types  of  life,  in 
fact,  urea  does  not  appear  as  such  in  the  excretory  products ; 
instead  we  find  uric  acid,  which  may  be  conceived  as  built  up 
of  two  molecular  urea  rests  and  one  tri-carbon  group.9 

1  W.  v.  Schroeder,  Zeitschr.  f.  physiol.  Chem.,  14,  576,  1890. 
8W.  Frey  (Gerhardt's  Clinic,  Basel),  Zeitschr.  f.  klin.  Med.,  72,  383,  1911. 
"Literature  upon  Excretion  in  Lower  Animals:    0.  v.  Fürth,  Vergl.  chem. 
Physiologie  d.  nieder.  Tiere,  Jena,  1903. 


ALKALOSIS  AND  ACIDOSIS  103 

Alkalosis  and  Acidosis. — The  views  as  to  the  special 
intoxication  picture  which  tends  to  manifest  itself  in  Eck 
fistula  animals  after  meat  diet  have  recently  undergone  an 
unexpected  change.  F.  Fischler,  in  Krehl's  Clinic  in 
Heidelberg,  from  observations  based  on  a  large  amount 
of  material,  differentiates  the  toxic  symptom  complex 
into  two  groups,  only  one  of  which  he  is  willing  to  at- 
tribute directly  to  the  meat  diet.  The  other  group  of 
symptoms  he  believes  to  be  determined  by  degenerative 
changes  in  the  liver,  referable  to  lesions  of  the  pancreas  pro- 
duced in  the  course  of  the  operation  and  to  consequent  escape 
of  free  pancreatic  ferment.  Against  these  latter  features 
of  the  toxic  complex  it  should  be  possible  to  prepare  the 
animal  by  appropriate  immunization  with  trypsin.  As  far 
as  the  features  of  meat  intoxication  are  concerned  (thus  in 
some  sense  isolated  in  purer  form),  Fischler  states  that  he 
has  never  met  among  his  Eck  fistula  dogs,  in  spite  of  ex- 
cessive meat  feeding,  excretion  of  an  acid  urine ;  and  because 
ostensibly  administration  of  phosphoric  acid  may  prevent  or 
cure  the  toxic  features,  he  believes  it  may  be  assumed  that  an 
"alkalosis"  is  of  importance  in  their  production,  a  patho- 
logical influence  of  alkaline  material  upon  the  tissues.10 
As  before  stated  other  authors  have  held  to  the  idea  of  an 
acidosis  in  the  study  of  this  and  of  allied  conditions,  and 
have  explained  the  increased  ammonia  elimination  in  con- 
sonance therewith.  The  same  view  is  applied,  for  example, 
in  the  hepatic  lesions  observed  by  Gautrelet  after  injection  of 
methylene  blue  or  sodium  fluoride.11  It  is  not  hard  to  un- 
derstand how  a  disinterested  observer  might  be  unable  to 
resist  a  feeling  of  general  distrust  in  such  a  position.  And 
yet  the  difference  may  be  only  an  apparent  one ;  and  perhaps 
the  following  may  approximate  the  truth.     One  should  recall 

10  F.  Fischler  (Med.  Clinic,  Heidelberg),  Deutsch.  Arch.  f.  klin.  Med.,  104, 
300, 1911. 

11  J.  Gautrelet,  with  K.  Mallie"  and  H.  Gravelat,  C.  R.  Soc.  de  Biol.,  60,  551, 
714,  1906. 


104  UREA.    HIPPURIC  ACID.    AMINOACIDS 

(v.  supra.,  p.  82)  that,  after  ingestion  of  a  meal  rich  in 
protein,  deamidization  processes  may  begin  at  once  in  the  in- 
testinal wall,  and  the  portal  blood  thereby  loaded  with  am- 
monium salts  passes  to  the  liver ,where  these  are  transformed 
into  urea.12  But  what  if  the  liver  be  excluded  or  so  seriously 
altered  that  formation  of  urea  does  not  take  place  in  the 
organ  as  normally  from  the  ammonia  which  is  swept  into  it 
with  the  portal  blood?  In  that  case  the  general  circulation, 
of  course,  will  next  be  flooded  with  ammonia,  probably  in  the 
form  of  carbonate.  As  doubtless  the  liver  does  not  monop- 
olize the  matter  of  forming  urea,  a  part  is  probably  taken 
up  by  other  organs  and  in  them  changed  into  urea,  while  an- 
other portion  of  the  ammonia  may  perhaps  be  rendered  inert 
by  acids  which  the  organism  mobilizes.  We  know  that  the 
organism  protects  itself  against  an  excess  of  acid  by  mobil- 
ization of  alkaline  material ;  and  it  is  perhaps  possible,  vice 
versa,  that  it  may  protect  itself  against  an  alkaline  excess  by 
mobilization  of  acid  substances,  or  possibly  by  elaboration  of 
unusual  kinds  and  quantities  of  acids,  as  in  the  acidosis 
actually  seen  in  a  number  of  hepatic  affections  (icterus 
catarrhalis)  .13  If,  however,  both  methods  of  protection  are 
insufficient  or  act  too  slowly,  the  result  may  ultimately  be  an 
alkaline  intoxication,  an  "alkalosis."  The  author  wishes, 
however,  not  to  be  misunderstood  as  saying  that  this  is 
actually  true;  these  suggestions  are  presented  only  in  the 
way  of  tentative  explanation. 

The  important  part  taken  by  ammonia  in  correction  of 
excessive  acidity  in  the  living  body  was  clearly  recognized  a 
number  of  years  ago  by  Walter,  in  Schmiedeberg 's  labora- 
tory. The  usually  more  marked  acid-resistance  of  carni- 
vores, in  contrast  with  vegetarian  animals,  is  apparently 

12  K.  Kowalevsky  and  M.  Markiewicz,  Biochem.  Zeitschr.,  4>  196,  1907;  cf. 
therein  the  older  literature,  especially  in  reference  to  the  differences  of  view  of 
Salaskin  and  Zaleski  and  of  Biedl  and  Winterberg. 

"N.  Janney  (F.  v.  Müller's  Clinic,  Munich),  Zeitschr.  f.  physiol.  Chem., 
16,  99,  1911. 


POSTCCENAL  UREA  EXCRETION  105 

fully  explained  by  the  difference  of  food.  According  to 
Eppinger  it  is  not  difficult  to  poison  with  acid  dogs  kept  on 
protein-free  diet;  conversely  the  inherently  low  acid-re- 
sistance of  rabbits  and  sheep  is  at  once  raised  by  food  rich 
in  protein.14  That  a  similar  defensive  influence  is  manifest 
also  from  injected  urea  and  aminoacids  is  denied  by  Pohl.13 

Arginase. — A  small  cleavage  fraction  of  the  nitrogen  in 
the  protein  molecule  arises,  not  by  the  roundabout  way  of 
total  dissociation  and  combustion,  but  by  direct  separation 
from  the  arginin-group  by  the  action  of  a  special  ferment, 
arginase  of  Kossel.  In  an  earlier  lecture  (Vol.  I  of  this 
series,  p.  94,  Chemistry  of  the  Tissues)  some  attention  was 
given  to  the  mode  of  action  of  the  latter.  Experiments  on 
protamines  have  indicated  that  arginase  is  able  to  seize  upon 
not  only  the  free  arginin  but  to  attack  even  that  which  is 
present  in  the  interior  of  the  protein  molecular  structure. 
Racemic  arginin  undergoes  asymmetrical  cleavage ;  creatin 
and  guanidin  are  not  affected.16  It  is  probable  that  some  of 
the  older  statements  in  literature  with  reference  to  fermen- 
tative production  of  urea 17  in  tissue  extracts  are  explicable 
as  due  to  the  influence  of  arginase. 

Postccenal  Urea  Excretion. — The  catabolism  of  ingested 
protein  in  the  normal  organism  occurs  so  promptly  that  the 
process  is  complete  within  the  course  of  a  few  hours.  Ob- 
servations upon  the  excretion  of  urea  from  hour  to  hour 
after  meals,  conducted  in  the  laboratory  of  Ernest  Freund, 
have  shown  that  in  normal  individuals  it  reaches  its  maxi- 
mal grade  as  early  as  four  to  five  hours  after  the  ingestion 

"H.  Eppinger,  Wiener  klin.  Wochenschr.,  1906,  No.  5;  Zeitschr.  f.  exper. 
Pathol.,  3,  530,  1906;  H.  Eppinger  and  F.  Tedesko,  Biochem.  Zeitschr.,  16,  207, 
1909. 

"J.  Pohl  and  E.  Münzer,  Centralbl.  f.  Physiol.,  20,  232,  1906;  J.  Pohl, 
Biochem.  Zeitschr.,  18,  24,  1909. 

"A.  Kossel  and  H.  D.  Dakin,  Zeitschr.  f.  physiol.  Chem.,  Ifl,  321,  1904; 
42,  181,  1904;  H.  D.  Dakin,  Journ.  of  Biol.  Chem.,  3,  435,  1907;  Rieszer  (Kos- 
sel's  Lab.,  Heidelberg) ,  Zeitschr.  f .  physiol.  Chem.,  49,  210,  1906. 

17  Ch.  Richet,  Chassevant,  Spitzer,  D.  Löwi;  cf.  O.  Löwi  ( Hofmeister's  Lab., 
Strassburg),  Zeitschr.  f.  physiol.  Chem.,  25,  512,  1898. 


106  UREA.    HIPPURIC  ACID.    AMINOACIDS 

of  nitrogenous  food.  If  the  ingested  material  has  been  in 
the  form  of  protein  already  advanced  in  catabolism  the  maxi- 
mum is  reached  more  quickly  and  the  greatest  urea  excretion 
is  to  be  noted  within  one  to  two  hours.18 

Quantitative  Estimation  of  Urea. — The  very  great 
physiological  importance  of  urea  is  apparently  sufficient 
reason  for  the  fact  that  there  has  been  no  dearth  of 
effort  to  improve  the  methods  for  its  quantitative  de- 
termination.19 The  old  method  of  Liebig  by  titration  with 
mercuric  nitrate  continues  to  appear  here  and  there  in  litera- 
ture; but  has  become  practically  unimportant,  and  efforts 
to  reinstate  the  method  have  attained  but  little  success.20 
The  most  modern  methods  as  a  rule  are  based  upon  the  prin- 
ciple of  transforming  the  urea  into  ammonia  by  hydrolytic 
agents  and  distilling  the  ammonia.  Other  nitrogenous  con- 
stituents present,  especially  those  of  basic  nature,  may  be 
separated  by  phosphotungstic  acid  (Pflüger-Bleibtreu- 
Schöndorf  method)  or  by  phosphomolybdic  acid  (Haskin's 
method).21  Some  prefer  to  at  least  partially  separate  the 
urea  from  other  constituents  by  the  Mörner-Sjöquist 
method  (precipitation  by  alcohol  and  ether  in  presence  of 
baryta) .  Hydrolysis  of  the  urea  is  accomplished  by  heating 
with  magnesium  chloride  and  hydrochloric  acid  (Folin's 
method),22  with  lithium  chloride  and  hydrochloric  acid 
(Saint  Martin),23  with  hydrochloric  acid  in  sealed  tubes 
(Salaskin  and  Zaleski),  with  sulphuric  or  hydrochloric  acid 

18  A.  Stauber  (E.  Freund's  Lab.,  Vienna),  Biochem.  Zeitschr.,  25,  187,  1910. 

18  Literature  upon  the  Quantitative  Estimation  of  Urea :  P.  Rona,  Handb.  d. 
biochem.  Arbeitsmethoden,  3',  774-782,  1910;  5',  295,  1911;  Neubauer-Huppert, 
Harnanalyse,  11th  ed.,  article  by  W.  Wiechowski,  I,  560-576,  1910;  C.  Neuberg, 
Der  Ham,  article  by  A.  C.  Anderson,  1,  631-641,  1911;  Ch.  Sallerin,  Journ.  de 
Physiol.,  1903,  No.  2. 

20  B.  Glaszmann  (Odessa),  Ber.  d.  Deutsch,  ehem.  Ges.,  39,  705,  1906. 

21  H.  D.  Haskins,  Jour,  of  Biol.  Chem.,  2,  243,  1906. 

22  O.  Folin,  Zeitschr.  f.  physiol.  Chem.,  36,  333,  1902;  37,  548,  1903;  E.  P. 
Cathcart,  Jour,  of  Physiol.,  35,  Proc.  viii,  1906. 

23  L.  G.  Saint  Martin,  C.  R.  Soc.  de  Biol.,  58,  89,  1905. 


HIPPURTC  ACID  107 

in  an  autoclave  (Benedict  and  Gephart,24  and  Henriques 
and  G-ammeltoft25),  or  very  conveniently  by  heating  with 
glacial  phosphoric  acid  in  open  vessels  (Braunstein),  or 
finally  by  heating  with  potassium  acetate  and  addition  of 
acetic  acid  and  zinc  (Folin).26  Naturally  there  are  any  num- 
ber of  variations  and  combinations  of  these  methods  pos- 
sible. In  spite  of  this  apparent  richness  it  must  be  confessed 
that  all  of  these  methods  are  indirect ;  and  that  in  case  other 
related  substances  occur  in  addition  to  urea,  with  their 
nitrogen  similarly  combined  in  the  structural  molecule,  it 
would  be  difficult  to  detect  them  against  the  urea,  to  say  noth- 
ing of  estimating  them. 

Attempts  to  determine  urea  quantitatively  by  splitting  it 
into  carbonic  acid  and  nitrogen  by  means  of  nitric  acid,  with 
subsequent  determination  of  nitrogen  by  Dumas'  method 
have  been  repeatedly  proposed.27 

HIPPURIC  ACID 

After  the  preceding  presentation  of  the  knowledge  we 
at  present  possess  of  the  formation  of  urea  in  the  living 
body,  our  attention  naturally  is  directed  to  other  nitrogenous 
end-products  of  protein  metabolism,  of  which  hippuric  acid 
may  first  be  dealt  with. 

As  is  well  known  hippuric  acid  is  a  combination  product 
arising  from  the  union  of  glycocoll  and  benzoic  acid : 

CH2.NH2  CHj.NH— CO.C«H6 

|  +  C6Hs.COOH=H20  +       | 

COOH  COOH. 

Source  of  Benzoic  Acid, — As  far  as  the  benzoic  acid  com- 
ponent is  concerned  our  knowledge  is  fairly  established.     It 

24  S.  R.  Benedikt  and  F.  Gephart,  Journ.  of  the  Amer.  Chem.  Soc,  SO, 
1760,  1908;  P.  A.  Levene  and  G.  H.  Meyer,  ibid.,  SI,  717;  G.  L.  Wolf  and  E. 
Osterberg,  ibid.,  SI,  421;  F.  W.  Gill,  F,  G.  Allison  and  H.  S.  Grindley,  ibid.,  SI, 
1078;    abstract  in  Centralbl.  f.  Physiol.,  23,  1909. 

25  V.  Henriques  and  S.  A.  Gammeltoft  ( Copenhagen ) ,  Skandin.  Arch.,  25, 
153,  1911. 

24  O.  Folin  (Harvard  Medical  School),  Jour,  of  Biol.  Chem.,  11,  507,  1912. 
"Th.  Ekekrantz,  with  K.  A.  Södermann  and  S.   Erikson    (Stockholm), 
Zeitschr.  f.  physiol.  Chem.,  16,  173,  1912;    79,  171,  1912. 


108  UREA.    HIPPURIC  ACID.    AMINOACIDS 

may  originate  from  one  or  other  of  two  sources :  First,  from 
aromatic  products  of  vegetable  food,  as  cinnamic  acid,  hy- 
drocinnamic  acid,  quinic  acid,  etc.,  which  in  metabolism  are 
catabolized  to  benzoic  acid.  It  is  not  remarkable,  therefore, 
that  the  quantity  of  benzoic  acid,  excreted  in  the  form  of 
hippuric  acid,  may  be  decidedly  increased  by  free  ingestion 
of  vegetables  and  fruit  (normally  present  in  human  urine  in 
amounts  of  0.7  to  1.  gram  daily,  on  mixed  diet) ;  and  that 
herbivora  eliminate  a  much  larger  quantity  than  carnivores. 
A  second  important  source  is  Phenylalanin,  one  of  the 
molecular  structural  units  of  protein.  Apparently  this 
compound  (cf.  Vol.  I  of  this  series,  p.  47,  et  seq.,  Chemistry 
of  the  Tissues)  readily  undergoes  complete  dissociation  in 
normal  metabolism;  however  the  phenylpropionic  acid 
which  is  produced  in  intestinal  putrefactions  from  Phenyl- 
alanin (cf.  Vol.  I  of  this  series,  p.  32,  Chemistry  of  the 
Tissues)  is  oxidized  freely  into  benzoic  acid  when  it  is 
resorbed. 


PHENYLALANIN       PHENYLPROPIONIC 
ACID 

BENZOIC 
ACID 

HIPPURIC 

ACID 

C«H6- 

-CH2 

CH.NH, 

1 

CeH6.  CH2 
CH2 

C6H5.  COOH 

— 

CeHs. 

CO— NH.CH2 
COOH 

COOH 

COOH 

The  importance  of  protein  putrefaction  to  the  production 
of  hippuric  acid  and  the  fact  that  in  dogs  whose  intestinal 
canal  has  been  largely  disinfected  by  means  of  calomel  the 
hippuric  acid  may  be  materially  lowered  in  the  urine  were 
fully  recognized  by  Baumann. 

The  history  of  the  second  component  part  of  hippuric 
acid,  glycocoll,  is,  however,  incomparably  more  complicated 
than  that  of  the  benzoic  acid.  Probably  a  clearer  conception 
of  the  processes  here  concerned  can  be  had  if  herbivorous 
and  carnivorous  animals  are  considered  separately,  as  it  is 
becoming  more  and  more  evident,  as  Ernst  Friedmann 28  has 

28  E.  Friedmann  and  H.  Tachau  (First  Med.  Clinic,  Berlin),  Biochem. 
Zeitschr.,  35,  88,  1911. 


HIPPURIC  ACID   FORMATION   IN   HERBIVORA     109 

stated,  "that  the  synthesis  of  hippuric  acid  in  rabbits  not 
only  occurs  in  different  organs  but  also  in  a  different  chem- 
ical manner  than  in  dogs." 

Hippuric  Acid  Elimination  in  Carnivora  and  in  Man. — 
In  Carnivora,  from  the  classical  perfusion  studies  of  Bunge 
and  Schmiedeberg,  the  kidney  is  the  sole  seat  of  hip- 
puric acid  synthesis.  It  should  here  be  recalled,  however, 
that  according  to  Schmiedeberg  the  kidney  contains  a  fer- 
ment, histozyme,  which  is  capable  of  splitting  hippuric  acid 
into  benzoic  acid  and  glycocoll,29  which  may  be  identical  with 
the  ferment  synthesizing  the  hippuric  acid,  as  we  have  come 
to  recognize  a  number  of  examples  of  the  reversibility  of 
enzyme  action.  Generally  speaking  the  phenomena  in  the 
Carnivora  present  nothing  surprising.  If  the  living  animal 
be  flooded  with  benzoic  acid  a  large  part  is  passed  uncom- 
bined ;  a  portion  unites  with  some  otherwise  unknown  reduc- 
ing substance ;  and  that  part  which  appears  in  the  urine  as 
hippuric  acid  is  not  so  great  that  it  cannot  be  explained  by 
the  amount  of  glycocoll  preexisting  in  the  protein  molecule 
and  separable  by  hydrolysis  from  the  dietary  and  tissue 
protein.30  (This  amount  of  glycocoll  corresponds  to  only 
4  to  5  per  cent,  of  the  total  nitrogen  mobilized  in  protein 
catabolism.) 

In  human  beings,  too,  in  the  opinion  of  Brugsch31  the 
findings  after  administration  of  benzoic  acid  apparently  do 
not  indicate  any  other  mode  of  formation  of  hippuric  acid, 
than  by  hydrolytic  protein  cleavage,  to  be  at  all  convincing. 
At  least  the  general  opinion  is  distinctly  contrary  to  such  a 
belief.32 

Hippuric  Acid  Formation  in  Herbivora. — In  herbivora 
an   essentially   different   situation   exists.      The  mutually 

28  N.  Mutch,  Journ.  of  Physiol.,  U,  176,  1912. 

30  Th.  Brugsch  and  J.  Hirsch,  Zeitschr.  f.  exper.  Pathol.,  S,  663,  1906. 
uTh.  Brugsch  and  J.  Tsuchija,  Zeitschr.  f.  exper.  Pathol.  5,  731,  737,  1909. 
32  J.  Lewinski    (Minkowski's  Clinic,  Greifswald),  Arch.  f.  exper.  Pathol., 
58,  397,  1908;  Th.  Brugsch,  Zeitsch.  f.  exper.  Pathol.,  5,  731,  1909. 


110  UREA.    HIPPURIC  ACID.    AMINO  ACIDS 

confirmatory  statements  of  Magnus -Levy,33  Wiechowski,34 
Ringer,35  and  Abderhalden 36  leave  no  doubt  that  when  ben- 
zoic acid  is  introduced  in  quantity  into  the  body  of  a  her- 
bivorous animal  about  a  third  or  more  of  the  total 
nitrogen  may  be  excreted  as  hippuric  acid.  It  is  true 
the  economy  is  not  operating  under  entirely  normal  condi- 
tions ;  there  is  probably  a  higher  cleavage  of  the  intrinsic 
proteins  under  the  toxic  influence  of  the  benzoic  acid  than 
normally.37  But  it  seems  altogether  improbable  that  the 
small  quantity  of  glycocoll  of  the  protein  molecule  would  be 
enough  to  form  the  nitrogenous  moiety  of  the  synthesis. 
(Abderhalden  has  shown,  too,  that  the  tissue  protein  of  veg- 
etarians is  no  richer  in  glycocoll  than  that  of  carnivores.)38 
Wiechowski,  who  met  in  some  of  his  experiments  on  rabbits 
with  more  than  fifty,  and  once  as  much  as  sixty- four,  per  cent, 
of  the  total  nitrogen  coming  from  protein  cleavage  appear- 
ing as  glycocoll,  believes  that  these  animals  actually  produce 
glycocoll,  as  he  found  that  the  synthesis  increased,  other 
things  being  equal,  the  longer  the  benzoic  acid  continued  in 
circulation,  and  remained  the  same  in  continuous  full-day  in- 
toxication. He  suspects,  too,  that  in  rabbits  glycocoll  is  the 
precursor  of  a  great,  if  not  the  greatest,  part  of  the  urea 
eliminated.  E.  Friedmann 39  has  been  able  to  show  by  per- 
fusion that  the  liver  of  the  rabbit  is  capable  of  transforming 
benzoic  acid  into  hippuric  acid ;  from  which,  as  the  amount 
of  hippuric  acid  synthesis  is  not  influenced  by  introduction 

33  A.  Magnus-Levy,  Münchener  med.  Wochenschr.,  1905,  No.  45;  Biochem. 
Zeitschr.,  6,  523,  1907. 

84  W.  Wiechowski  (Pharmacol.  Instit.,  Prague),  Hofmeister's  Beitr.,  7,  258- 
262,  1905. 

38  A.  J.  Ringer  (Cornell  Univ.,  New  York),  Jour,  of  Biol.  Chem.,  10, 
327,  1911. 

36  E.  Abderhalden  and  P.  Hirsch,  Zeitschr.  f.  physiol.  Chem.,  78,  292, 
1912;    cf.  also  A.  A.  Epstein  and  S.  Bookman   (New  York),  v.  infra. 

S'A.  A.  Epstein  and  S.  Bookman  (New  York),  Jour,  of  Biol.  Chem.,  10, 
353,  1911. 

88  E.  Abderhalden,  A.  Gigon  and  E.  Strauss,  Zeitschr.  f .  physiol.  Chem.,  51, 
311,  1907. 

3»E.  Friedmann  and  H.  Tachau,  1.  c. 


SYNTHETIC  SOURCE  OF  GLYCOCOLL  111 

of  actual  glycocoll,  it  may  be  deduced  that  the  glycocoll  com- 
ponent or  a  predecessor  thereof  originates  in  the  liver  of  the 
rabbit  under  the  influence  of  benzoic  acid. 

Behavior  of  Benzoylated  Aminoacids. — How  are  all 
these  considerations  to  be  harmonized?  The  possibility  has 
been  suggested  that  the  benzoic  acid  primarily  binds  the 
NH2  group  of  the  aminoacids  and  adheres  to  it,  the  remain- 
ing carbon  skeleton  of  the  molecule  undergoing  disin- 
tegration : 


LEUCIN 

BENZOYL-LEUCIN 

r 

HIPPURIC   ACID 

CH,           CH, 

\    / 
CH 

CH3                CH3 

\      / 

CH 

CH2.NH— CO.CeH» 

CH2 

1 

— >          CH2 

1 

-^ 

COOH. 

CH.NH2 

1 

CHNH- 

-CO.C.H, 

COOH 

COOH 

A  number  of  feeding  experiments  by  Magnus-Levy  with 
benzoylated  aminoacids  cannot  be  regarded  as  supporting 
this  theory.40 

Synthetic  Source  of  Glycocoll  from  Acetic  Acid  and 
Ammonia. — At  present  appearances  again  favor  the  idea 
that  glycocoll  may  originate  synthetically  from  ammonia  and 
acetic  acid.  R.  Cohn 4 1  years  ago  observed  in  the  laboratory 
of  Jaffe  in  Heidelberg  that  /u.-nitrobenzaldehyde  or 
/u-toluidine,  introduced  into  a  living  rabbit,  was  transformed 
into  /A-aminobenzoic  acid,  but  that  this  combined  with  acetic 
acid: 

NITROBENZALDEHYDE  AMINO-BENZOIC  ACETYLAMINOBENZOIC 

ACID  ACID 


C5H^ 


NOj  NH2  NH.CO.CH3 

>■  CßH.jCr  >•  CeH,)^ 

COOH  COOH. 


These  examples  of  a  combination  of  acetic  acid  with  am- 
monia rests  suggested  the  idea  of  determining  whether  the 

40  A.  Magnus-Levy,  Biochem.  Zeitschr.,  6,  541,  1907. 

a  R.  Cohn,  Zeitschr.  f.  physiol.  Chem.,  11,  274,  1892 ;   Arch.  f.  exper.  Pathol., 
53,  435,  1905. 


112  UREA.    HIPPURIC  ACID.    AMINOACIDS 

rabbit  is  able  to  form  glycocoll  synthetically  from  ammonia 
and  acetic  acid ;  and  as  a  matter  of  fact  a  very  appreciable 
increase  in  hippuric  acid  elimination  was  observed  in  several 
experiments  in  which  ammonium  acetate  and  benzoic  acid 
were  simultaneously  administered.  Although,  it  is  true, 
these  studies  are  not  definitely  conclusive,  E.  Friedmann42 
has  recently  declared  the  possibility  of  a  synthetic  formation 

of  glycocoll  from  acetic  acid  and  ammonia,  with  the  very 

/COH  \ 
actively  combining  glyoxylic  acid       I  as  a  possible 

intermediate  product.     A  simple  synthesis  of  acetic  acid 

/CH,        \ 

with  ammonia  can  result  only  in  acetamide  (   I  )  but 

VCO  NH8/ 

/H 

never  in  glycocoll  f^^^Y  Here  may  be  a  special   (c0 
&J  VCOOH    /  VI 

XCOOH 

instance  of  the  previously  discussed  (v.  supra.,  p.  69) 
synthesis  of  aminoacids  from  a-ketonie  acids  and  ammonia 
following  the  schema : 

R  R 

CO        +     NH,    ^±.    CH.NH2-f-0 

COOH  COOH. 

Glycocoll  and  Ornithin  as  Detoxifying  Agents. — We 
have  come  to  regard  this  synthetic  union  of  glycocoll 
and  benzoic  acid  as  peculiarly  important  in  that  it  may 
be  looked  upon  as  eliminating  the  toxic  benzoic  acid. 
It  is  well  known  that  quite  a  number  of  other  aromatic  acids 
analogous  to  benzoic  acid  may  combine  with  glycocoll  in  the 
economy.  One  of  these,  phenylpropionic  acid  (C6H5.  CH2. 
CH2.  COOH.),  Dakin  has  shown  to  be  very  toxic  to  cats,43 
being  transformed  in  the  animal  partly  into  acetophenone 
(C6H5.CO.CH3) ;  although  its  synthetic  compound  with 
glycocoll,  phenylpropionylglycocoll  ( C6H5.CH2.CH2.CO-NH. 

42  E.  Friedmann  and  H.  Tachau,  1.  c,  p.  90. 

43  H.  D.  Dakin  (C.  A.  Herter's  Lab.,  New  York),  Jour,  of  Biol.  Chem.,  5, 
413,  1908. 


QUANTITATIVE  ESTIMATION  OF  HIPPURIC  ACID    113 

CH2.COOH)  is  nontoxic.  This  suggests  the  thought  that 
perhaps  in  another  synthetic  process  which  takes  place  in  the 
body,  between  glycocoll  and  cholic  acid,  with  formation  of 
the  glycocholic  acid  of  the  bile  (Vol.  I  of  this  series,  p.  306, 
Chemistry  of  the  Tissues),  glycocoll  may  be  playing  the  part 
of  a  detoxifying  agent.  Benzoic  acid  introduced  into  living 
birds  is,  however,  not  rendered  harmless  by  glycocoll;  in 
birds  another  cleavage  product  of  the  protein  molecule  takes 
its  place,  as  pointed  out  by  the  celebrated  Königsberg  phar- 
macologist,  M.   Jaffe    (recently   deceased),   viz.:   Ornithin 

/CH2NH2' 

I 
CH2 

CH2        |,  which,  as  is  known,  originates  from  cleavage   of 

CN.NH2 

\COOH 

arginin  (Vol.  I  of  this  series,  p.  10,  Chemistry  of  the  Tis- 
sues).44 This  appears  in  the  urine  as  a  dibenzoyl  compound, 
ornithuric  acid : 

CH2.NH  —  CH2— CHj—  CH.NH—  COOH 
CO.CeHs  CO.C6Hs. 

Quantitative  Estimation  of  Hippuric  Acid. — Before 
leaving  this  part  of  the  subject  reference  should  be 
made  to  the  method  of  quantitative  determination  of  hip- 
puric acid,  a  substance  of  decided  importance  physiologi- 
cally. The  hippuric  acid  in  an  animal  fluid  may  be  estimated 
as  such ;  or  its  glycocoll  may  be  determined ;  or  the  benzoic 
acid.  The  first  of  these  plans  is  followed  in  the  method  of 
Bunge  and  Schmiedeberg,  in  which  the  hippuric  acid  is 
extracted  by  acetic  ether  from  urine,  purified  by  passing 
through  animal  charcoal,  and  weighed.  Henriques  and 
Sörensen  employ  their  method  of  f  ormol  titration  to  estimate 
the  glycocoll  separated  out  from  the  hippuric  acid. 

**  In  the  text  referred  to  in  the  formula  for  Ornithin  an  unfortunate  typo- 
graphical error  occurs,  in  that  one  CIL  group  too  many  is  shown. 

R 


114  UREA.    HIPPURIC  ACID.    AMINOACIDS 

The  fact  that  hippuric  acid  is  exceedingly  unstable,  being 
readily  dissociated  by  evaporating  the  urine  in  weak  alkaline 
reaction  by  heat,  or  by  urinary  fermentation,  has  led  to  the 
introduction  of  an  increasing  number  of  methods  in  which 
the  hippuric  acid  is  estimated  as  benzoic  acid.  The  latter 
compound  because  of  its  stability  and  ready  solubility  in 
ether  and  other  solvents  offers  certain  advantages.45  The 
method  of  Wiechowski 46  is  exact  but  time  consuming,  the 
benzoic  acid  being  separated  by  aqueous  distillation. 
Steenbock 47  oxidizes  the  alkalinized  urine  with  peroxide  of 
hydrogen,  separates  the  phenols  with  bromine  water  after 
acidulation,  and  removes  the  benzoic  acid  by  shaking  with 
ether;  after  evaporation  of  the  ether  the  benzoic  acid  is 
sublimed  in  a  special  glass  apparatus  and  weighed.  Folin 48 
oxidizes  the  urine  with  nitric  acid,  extracts  with  chloroform, 
washes  the  chloroform  solution  with  a  saturated  salt  solu- 
tion containing  hydrochloric  acid  and  determines  the  benzoic 
acid  by  titration  with  alcoholic  sodium  hydrate  solution. 

Recently  one  of  the  author's  pupil's,  Hryntschak,49  has 
elaborated  what  is  apparently  a  very  satisfactory  method. 
The  urine  is  oxidized  after  treatment  with  boiling  sodium 
hydrate  solution  by  an  excess  of  potassium  permanganate ; 
the  manganese  which  separates  is  dissolved  by  sodium  bisul- 
phite and  sulphuric  acid;  and  the  clear  colorless  fluid  then 
extracted  with  ether.  After  evaporation  of  the  ether  the 
benzoic  acid  is  taken  up  with  chloroform,  and  finally  in 
pure,  crystallized  form  is  weighed.  Control  determinations 
of  hippuric  acid  in  known  solutions  show  that  the  method  is, 

44  R.  Cohn,  Th.  Pfeiffer,  C.  Bloch,  R.  Riecke,  W.  Wiechowski.  Literature 
upon  the  Estimation  of  Hippuric  Acid:  Th.  Hryntschak,  Biochem.  Zeitschr.,  43, 
316,  1912.     Conducted  under  direction  of  O.  v.  Fürth. 

46  W.  Wiechowski,  Hofmeister's  Beitr.,  7,  262,  1906. 

"H.  Steenbock  (Univ.  of  Wisconsin),  Jour,  of  Biol.  Chem.,  11,  201,  1912. 

"O.  Folin  and  F.  F.  Flanders  (Harvard  Med.  School,  Boston),  Jour,  of 
Biol.  Chem.,  11,  257,  1912. 

49 1.  c. 


AMINOACIDS  IN  NORMAL  URINE  115 

with  careful  practice  of  precautions,  capable  of  recovering 
95  to  98  per  cent. 

ELIMINATION  OF  THE  AMINOACIDS 

The  above  consideration  of  the  part  of  glycocoll  in  inter- 
mediate metabolism  serves  to  introduce  another  interesting 
problem,  that  of  the  conditions  under  which  thea-aminoacids, 
the  essential  products  of  the  catabolism  of  the  protein  mole- 
cule, may  escape  the  normal  combustion  and  appear  in 
appreciable  quantity  in  the  urine. 

Aminoacids  in  Normal  Urine. — That  a-aminoacids,  at 
least  their  optically  active  forms,  which  are  normally  struc- 
tural parts  of  the  proteins,  may  easily  undergo  complete 
disintegration  is  beyond  question  and  has  been  proven 
experimentally  many  times;  although  in  case  of  artificial 
introduction  of  formed  aminoacids  it  has  been  proved  that 
a  portion  sometimes  escapes  as  such  in  the  urine.50  Nor- 
mally, the  amount  of  aminoacids  in  the  urine  is,  of  course, 
quite  small.  Different  explanations  have  been  proposed  for 
this  fact,  as  it  has  been  determined  that  hippuric  acid  in 
standing  urine  is  very  readily  subject  to  cleavage  51  from 
action  of  bacteria,  and  its  glycocoll  may  then  be  detected 
by  the  naphthalinsulphochloride  method.  Other  aminoacids 
than  glycocoll  have  apparently  thus  far  not  been  certainly 
obtained  from  normal  urine.52  However,  it  might  be  easily 
conceived  how,  if  small  quantities  of  glycocoll,  which  had 
escaped  synthesis  into  hippuric  acid  or  had  been  produced 


50  E.  Abderhalden  and  P.  Bergell,  Zeitschr.  f.  physiol.  Chem.,  39,  10,  1903; 
K.  Stolte  (F.  Hofmeister's  Lab.,  Strassburg),  Hofmeister's  Beitr.,  5,  15,  1904; 
M.  Plaut  and  H.  Reese  (under  direction  of  G.  Embden),  Hofmeister's  Beitr., 
7,  425,  1905;  E.  Reisz,  ibid.,  8,  332,  190G;  S.  Oppenheimer,  ibid.,  10,  273,  1907; 
R.  Hirsch,  Zeitschr.  f.  exper.  Pathol.,  1,  141,  1905;  E.  Abderhalden  and  J. 
Markwalder,  Zeitschr.  f.  physiol.  Chem.,  12,  63,  1911;  E.  Abderhalden,  A. 
Furmo,  E.  Goebel  and  P.  Stübel,  ibid.,  74,  481,  1911. 

aY.  Seo  (Minkowski's  Clinic,  Greifswald),  Arch.  f.  exper.  Pathol.,  58,  440, 
1908. 

62  E.  Abderhalden  and  A.  Schittenhelm,  Zeitschr.  f .  physiol.  Chem.,  $7, 
339,  1906. 


116  UREA.    HIPPURIC  ACID.    AMINOACIDS 

by  a  fermentative  cleavage  of  formed  hippuric  acid,  were 
present  in  the  blood  and  tissues,  they  might  enter  the  urine.53 
Elimination  of  Aminoacids  in  Disease. — It  is  of  more 
interest  than  the  occurrence  of  small  amounts  of  aminoacids 
in  normal  urine  to  know  that  in  certain  pathological  con- 
ditions the  excretion  of  these  compounds  has  been  found 
to  be  notably  increased,  as  in  some  of  the  severe  infectious 
fevers  (typhus  fever,  spotted  fever,  scarlet  fever,  pneu- 
monia and  small  pox,  but  not  in  measles  and  diphtheria).54 
A  number  of  investigators  have  found  increased  aminoacid 
excretion  in  phosphorus  poisoning  and  acute  yellow  atrophy 
of  the  liver  55 ;  a  symptom  which,  as  already  stated,  has 
been  referred  to  the  increased  autolysis  in  the  liver  peculiar 
to  these  conditions.  It  is  noted  also  in  other  severe 
hepatic  disturbances,56  as  in  poisoning  by  arsenuretted 
hydrogen,  prussic  acid,  and  in  various  degenerative 
changes  in  the  liver,  especially  cirrhosis,  cancer,  fatty 
degeneration  and  syphilis.  It  was  at  one  time  hoped  that 
the  recognition  of  an  increase  in  aminoacid  elimination, 
especially  after  purposeful  administration  of  aminoacids 
(as  it  were  an  " alimentary  aminuria"),  might  be  utilized  in 
diagnosis  as  to  the  functional  integrity  of  the  liver.57     How- 

BG.  Embden  and  A.  Marx,  H'ofmeister's  Beitr.,  11,  308,  190S;  A.  Bingel 
(G.  Embden's  Lab.,  Frankfurt  a.  M.),  Zeitschr.  f.  physiol.  Chem.,  51,  382,  1908; 
G.  Forssner  (F.  v.  Miiller's  Clinic),  ibid.,  41,  15,  1906;  F.  Samuely,  ibid.,  47, 
376,  1906;  G.  Oehler,  Biochem.  Zeitschr.,  21,  48,  1909;  A.  v.  Reusz,  Wiener 
klin.  Wochenschr.,  22,  158,  1909. 

Mv.  Jaksch,  Zeitschr.  f.  klin.  Med.,  41,  1,  1902;  50,  167,  1903;  R.  Erben, 
Zeitschr.  f.  Heilk.,  25,  33,  1904;  Zeitschr.  f.  physiol.  Chem.,  43,  320,  1905; 
Internat.  Beitr.  z.  Path.  u.  Ther.  d.  Ernährungsstörungen,  2,  252,  1911;  A. 
Primavera  (Naples),  Giorn.  Internaz.  di.  Scienze  Med.,  30;  abstract  in  Biochem. 
Centralbl.,  9,  No.  880,  1909-10. 

"Literature  upon  Metabolism  in  Phosphorus  Poisoning,  Acute  Yellow 
Atrophy  of  the  Liver,  etc.:    C.  Neuberg,  Handb.  d.  Biochem.,  4",  336-337,  1910. 

MW.  Frey  (D.  Gerhardt's  Clinic,  Basel),  Zeitschr.  f.  klin.  Med.,  12,  383, 
1911;  F.  Falk  and  P.  Saxl  (v.  Noorden's  Clinic,  Vienna),  ibid.,  13,  131,  1911. 
N.  Masuda  (Fr.  Kraus'  Clinic,  Berlin),  Zeitschr.  f.  exper.  Pathol.,  8,  629,  1911. 

"K.  Gliiszner,  Zeitschr.  f.  exper.  Pathol.,  4,  336,  1907;  H.  Jastrowitz 
(Med.  Clin.,  Prague),  Arch.  f.  exper.  Pathol.,  59,  463,  1908. 


ELIMINATION  OF  AMINOACIDS  117 

ever,  it  is  doubtful  at  present  whether  any  practical  result 
will  be  attained.58  Increase  in  the  aminoacid  excretion  has 
also  been  met  in  a  variety  of  conditions  in  which  it  is  not  at 
all  evident  that  we  are  dealing  with  disturbances  of  the 
hepatic  function,  as  in  pregnancy,59  gout,60  diabetes,61 
leukaemia,62  and  after  large  hemorrhages.63  Physiologically 
the  excretion  of  aminoacids  is  apparently  greater  in  infants 
than  in  grown  persons.64  It  is  worthy  of  special  attention 
that  an  enormous  access  of  aminoacids  occurs  in  the  urine  of 
hibernating  marmots,  with  corresponding  reduction  in  the 
urea.65  It  may  well  be  a  time  will  come  when  it  will  be 
possible  to  recognize  and  appreciate  a  common  basis  for 
these  heterogeneous  facts ;  but  at  the  present  as  far  as  the 
author  is  concerned  it  is  entirely  impossible  to  offer  any  sug- 
gestion save  by  labored  and  arbitrary  theorization.  How- 
ever much  the  author  realizes  the  importance  of  hypotheses 
towards  future  discovery,  he  feels  that  in  this  case  the 
metabolic  chemist  has  every  reason  for  keeping  close  to 
the  fundamental  facts  lest  he  risk  loss  of  all  the  footing  on 
which  he  stands. 

68  Cf.  H.  Ishihara,  Biochem.  Zeitschr.,  41,  315,  1912  (under  direction  of 
O.  v.  Fürth). 

59  E.  C.  van  Leersum,  Biochem.  Zeitschr.,  11,  121,  1908;  C.  Rolla, 
Pathologica,  2,  575;  abstract  in  Jahresber.  f.  Tierchem.,  40,  1910;  F.  Falk  and 
O.  Hesky  (Clinic  of  v.  Noorden  and  Schauta,  Vienna),  Zeitschr.  f.  klin.  Med., 
71,  261,  1910. 

"•A.  Ignatowski  (Fr.  v.  Miiller's  Clinic,  Munich),  Zeitschr.  f.  physiol. 
Chem.,  4%,  388,  1904;  cf.  to  the  contrary,  A.  Lipstein  (v.  Noorden's  Clinic, 
Frankfurt  a.  M.),  Hofmeister's  Beitr.,  7,  527,  1906. 

"Mies,  München,  med.  Wochenschr.,  1894,  671;  Nicola,  Giorn.  d.  R.  Acad, 
di  Torino,  anno  67,  Ser.  IV,  Vol.  10,  p.  83,  1904;  E.  Abderhalden,  Zeitschr.  f. 
physiol.  Chem.,  U,  51,  1905:  M.  Labbe  and  H.  Bith,  C.  R.  Soc.  de  Biol.,  71,  348, 
1911. 

42  Ignatowski,  1.  c. 

62  D.  Fuchs   (Klausenberg),  Zeitschr.  f.  physiol.  Chem.,  69,  482,  1910. 

64  F.  W.  Schultz,  Jahresber.  f.  Kinderheilk.,  72,  Ergänzungsheft,  1910; 
R.  Kadlich  and  P.  Grosser,  ibid.,  75,  4. 

M  K.  Nagai  (Verworn's  Lab.,  Göttingen),  Zeitschr.  f.  allgem.  Physiol.,  9, 
306-334,  1906. 


118  UREA.    HIPPURIC  ACID.    AMINOACIDS 

Cystinuria  and  Diaminuria. — Our  interest  in  the  dis- 
covery of  the  aminoacids  in  the  urine  has  taken  on  special 
interest  since  we  have  learned  to  look  upon  two  rare  and 
important  metabolic  anomalies,  cystinuria  and  diaminuria, 
as  belonging  in  the  same  category.66  It  has  been  known 
for  a  long  time  that  cystin  is  excreted  in  the  urine  and  may 
be  found  in  concretions  and  in  urinary  sediments  in  its  strik- 
ing crystalline  form  (regular  hexagonal  plates).  E.  Bau- 
mann and  L.  v.  Udranzky  have  recognized  in  a  case  of 
cystinuria  the  presence  of  diamines  in  the  urine.  In  the 
light  of  A.  Ellinger's  investigations,  previously  considered 
(v.  Vol.  I  of  this  series,  p.  34,  Chemistry  of  the  Tissues), 
there  can  be  little  doubt  that  in  such  a  subject  cer- 
tain of  the  " building  stones"  of  the  protein  molecule  come, 
so  to  speak,  to  the  surface  of  metabolism  which  should  or- 
dinarily undergo  complete  disintegration  in  its  depths ;  and 
that  here  we  have  to  deal  on  one  hand  with  the  sulphur- 

CH2.S-S-CH2 
containing   fraction  of  protein,   cystin  I  CH.NH2    CH.NH2 

^COOH  COOH 
and  on  the  other  hand  with  the  diamines,  putrescin  (tetra- 
methylendiamine  —  CH2.NH2  -  CH2  -  CH2  -  CH2.NH2)  and 
cadaverin  (pentamethylendiamine — CH2.NH2-  CH2  -  CH2- 
CH2- CH2.NH2),  the  first  arising  from  Ornithin  and  the 
latter  from  lysin  by  separation  of  C02.  Ornithin  is,  repeating 
a  statement  previously  made  in  the  present  lecture,  a  cleav- 
age derivative  of  arginin.  The  true  significance  of  cystinuria 
and  diaminuria  was  first  correctly  explained  by  the  observa- 
tions of  A.  Löwy  and  C.  Neuberg.  These  writers  noted  in  an 
individual  under  their  observation  that  he  was  unable  to 
oxidize  introduced  mono-  and  di-aminoacids,  which  in  the 

C6  Literature  upon  Cystinuria  and  Diaminuria:  E.  Friedmann,  Ergebn.  d. 
Physiol.,  1,  16,  1902;  F.  Umber,  Lehrb.  d.  Ernähr,  u.  d.  Stoffwechselkr.,  1909, 
pp.  385-389;  J.  Wohlgemuth,  Handb.  d.  Biochem.,  3',  192-195,  1900;  A.  Ellinger, 
ibid.,  3',  660-664,  1910;  C.  Neuberg,  ibid.,  It",  338,  1910;  C.  E.  Simon  and  D.  G. 
Campbell,  Johns  Hopkins  Hospital  Bulletin,  15,  365,  1904. 


CYSTINURIA  AND  DIAMINURIA  119 

normal  economy  undergo  complete  destruction.  While  in- 
gested mono-aminoacids  appeared  in  part  in  the  urine  un- 
changed, cadaverin  was  excreted  when  lysin  was  introduced 
and  putrescin  when  arginin  was  given.  According  to  Neu- 
berg  we  should  recognize  different  grades  of  cystinuria, 
which  is  a  pronounced  familial  diathesis:  (a)  mild  cases 
who  excrete  cystin  but  who  oxidize  other  aminoacids,67  and 
(b)  moderately  severe  cases  by  whom  no  mono-aminoacids  at 
all  are  spontaneously  excreted  but  in  whom  an  alimentary 
aminuria  and  diaminuria  exists.  Only  in  (c)  the  most 
severe  cases  are  the  aminoacids  spontaneously  excreted,  as 
in  an  instance  observed  by  Abderhalden  and  Schittenhelm. 
Special  interest  attaches  to  the  case  of  a  cystinuric  indi- 
vidual, who  was  able  to  use  up  aminoacids  but  poorly,  dipep- 
tids  to  better  advantage,  but  with  still  more  efficience  the 
more  complex  protein  derivatives.68  It  can  be  seen  from 
such  a  case  that  this  anomaly  need  not  be  associated  with 
serious  metabolic  faults  and  may  continue  for  years  without 
manifesting  itself  by  evident  symptoms.  As  previously 
stated  (Vol.  I  of  this  series,  p.  307,  Chemistry  of  the  Tis- 
sues), cystin  is  closely  related  with  taurin,  one  of  the  two 
synthetic  products  of  cholic  acid  occurring  in  the  bile: 

CYSTEIN  TAURIN 

CH2.SH  CH2.HSO, 

CH.NH,     — >■         CH2.NHj. 

COOH 
If  cystin  be  administered  to  normal  individuals  a  large 
part  of  its  sulphur  appears  in  the  urine  in  oxidized  form,  as 
sulphuric  acid.  If,  however,  along  with  cystin  sodium 
cholate  be  given,  in  the  first  place  taurocholic  acid  in  the  bile 
is  apparently  increased,69  and  a  correspondingly  increased 

*  Cases  of  Chas.  E.  Simon,  C.  Alsberg  and  0.  Folin,  A.  E.  Garrod  and  W.  H. 
Hurtley,  H.  B.  Williams  and  C.  G.  L.  Wolf. 

es  A.  Löwy,  and  C.  Neuberg,  Biochem.  Zeitschr.,  2,  438,  1906. 

«•G.  v.  Bergmann  (F.  Hofmeister 's  Lab.,  Strassburg),  Hofmeister's  Beitr., 
4,  192,  1904. 


120  UREA.    HIPPURIC  ACID.    AMINOACIDS 

amount  of  the  sulphur  of  the  cystin  fails  to  undergo  oxida- 
tion into  sulphuric  acid.  In  a  cystinuric  individual,  however, 
this  latter  result  of  administration  of  cholic  acid  does  not  oc- 
cur, presumably  depending  upon  a  failure  to  synthesize 
taurocholic  acid.70  An  interesting  addendum  to  these  obser- 
vations is  afforded  by  a  case  of  hepatic  cirrhosis  presenting 
a  combination  of  acholia  and  cystinuria,  interpreted  as  an 
instance  of  failure  of  normal  taurocholic  acid  synthesis  be- 
cause of  disease  of  the  hepatic  parenchyma,  as  a  result  of 
which  the  available  (for  transformation  into  taurin)  cystin 
passed  unchanged  into  the  urine.71 

Quantitative  Determination  of  the  Aminoacids. — The 
great  number  of  physiological  and  pathological  problems 
related  to  the  excretion  of  aminoacids  in  the  urine  is 
sufficient  explanation  for  the  amount  of  attention  devoted 
in  recent  years  to  the  elaboration  of  methods  for  the  isolation 
and  estimation  of  these  substances.  For  isolating  the  amino- 
acids the  method  of  binding  them  with  naphthalinsulpho 
chloride  or  with  naphthylisocyanate  is  of  service  (Vol.  I  of 
this  series,  p.  15,  Chemistry  of  the  Tissues).  For  estimation 
of  the  aminoacid  nitrogen  the  van  Slyke  method  (ibid.,  p. 
18),  depending  upon  displacement  of  the  aliphatic  amino 
group  by  nitric  acid,72  will  be  found  valuable;  or,  too,  the 
formol-titration  method  of  Henriques  and  Sörensen.  The 
latter  is  based  on  the  fact  that  a-aminoacids  in  excess  quanti- 
tatively bind  formaldehyde : 


R.  CH.  NH2  H  R.  CH.  N  =  c/ 

|  +  I  =     H20  +  | 

C  O  O  H  COH  COOH. 


70  E.  C.  Simon  and  D.  G.  J.  Campbell,  Johns  Hopkins  Hosp.  Bull.,  15,  365, 
1904. 

71  Observation  of  Morawsky,  cited  by  J.  Wohlgemuth,  Deutsche  Klinik,  11, 
329,  1907. 

"P.  A.  Levene  and  D.  D.  van  Slyke  (Rockefeller  Instit.,  New  York),  Jour, 
of  Biol.  Chem.,  12,  301,  1912.  This  method  serves  to  determine  not  only  the 
free  aminoacids,  but  also  those  combined  in  form  of  Polypeptids,  etc.,  in  the 
urine. 


DETERMINATION  OF  AMINOACIDS  121 

If  the  solution  be  carefully  neutralized  before  its  trans- 
formation with  formaldehyde,  the  masking  of  the  basic  NH2 
groups  becomes  evident  at  once  by  the  development  of  an 
acid  reaction ;  and  as  a  matter  of  fact  this  increase  of  acidity 
after  addition  of  formol,  which  may  be  determined  by  titra- 
tion, is  a  precise  measure  of  the  amount  of  amino  groups 
present.  It  cannot  be  questioned  that  the  method,  the 
technique  of  which  has  received  much  criticism  and  has  been 
improved  in  a  number  of  ways,  is  really  a  valuable  addition 
to  our  scientific  equipment.73 

73  V.  Henriques  and  S.  P.  L.  Sörensen,  Zeitschr.  f.  physiol.  Chem.,  63,  27, 
1909;  6Jf,  120,  1910;  V.  Henriques,  ibid.,  60,  1,  1909;  S.  P.  L.  Sörensen, 
Biochem.  Zeitschr.,  25,  1,  1910;  H.  Malfatti,  Zeitschr.  f.  physiol.  Chem.,  61, 
499,  1909;  66,  152,  1910;  L.  de  Jager,  ibid.,  65,  185,  1910;  67,  1,  105,  1910;  W. 
Frey  and  A.  Gigon,  Biochem.  Zeitschr.,  22,  309,  1909;  T.  Yoshida,  ibid.,  2S,  239, 
1909;  cf.  also  Neubauer-Huppert's  Analyse  des  Harnes,  2d  ed.,  article  by  A. 
Ellinger,  1,  641  to  647,  1910;  Neuberg,  Der  Ham.,  article  by  A.  C.  Andersen, 
1,  569-630,  1911. 


CHAPTER  VI 

CREATIN  AND  CREATININ.     OTHER  URINARY  BASES. 
OXYPROTEIC  ACIDS.    UROCHROME. 

CREATIN   AND    CREATININ 

In  the  current  lecture  two  important  end-products  of 
metabolism  will  first  be  carefully  considered,  creatin  and 
Creatinin.  The  importance  of  these  two  closely  related  sub- 
stances is  at  once  apparent  when  we  recall  that  a  fully  grown 
human  being  excretes  as  an  average  about  one  gram  of 
Creatinin  in  the  urine  in  the  course  of  twenty-four  hours,  and 
that  this  substance,  from  a  quantitative  standpoint,  is  a 
prominent  member  of  the  group  of  excretory  products  which 
represent  the  nitrogen  fraction  escaping  transformation 
into  urea. 

In  attempting  to  present  a  precise  statement  of  the 
knowledge  we  possess  as  to  the  nature  and  importance  of 
these  substances,  the  first  impression  obtained  by  tracing 
the  history  of  this  metabolic  problem  is  a  very  confusing  and, 
indeed,  a  depressing  one.  If,  however,  one  works  with  de- 
termination through  the  tangle  of  actual  and  seeming  con- 
tradiction which  involves  the  subject,  he  will  gradually 
realize  a  pleasant  satisfaction  in  learning  that  conditions  are 
not  really  as  bad  as  they  at  first  appear.  The  pioneer 
work  of  the  last  ten  years  has  basically  cleared  the  ground, 
and  if  to-day  a  survey  be  made  free  view  in  more  than  one 
direction  is  found  possible. 

Quantitative  Estimation. — In  the  development  of  the 
creatin  problem  may  be  seen,  as  often  is  the  case  in  physio- 
logical chemistry,  how  actual  progress  first  became  appreci- 
able after  analytical  chemistry  had  provided  an  applicable 
method  of  estimation  with  which  the  physiological  investiga- 
tor could  work  with  satisfaction.  In  this  instance  we  are 
much  indebted  to  0.  Folin 1  for  his  carefully  elaborated 


O.  Folin,  Zeitschr.  f.  physiol.  Chem.,  41,  223,  1904. 
122 


RELATION  BETWEEN  CREATIN  AND  CREATININ     123 

method  for  the  determination  of  Creatinin.  Jaffe  's  reaction, 
with  its  bright  red  color  produced  by  the  addition  of  sodium 
hydrate  and  picric  acid  to  Creatinin,  is  made  use  of  in  the 
method  for  colorimetric  determination.  Creatin  may  like- 
wise be  estimated  after  complete  transformation  into  Crea- 
tinin by  chemical  agents  (as  by  the  process  of  Benedict 
and  Meyers  2  by  heating  the  creatin  with  hydrochloric  acid  in 
an  autoclave).3  It  would  unquestionably  be  very  desirable 
to  discover  a  direct  method  of  satisfactorily  estimating 
creatin.  Whether  the  proposal  to  utilize  the  orange  color 
which  diacetyl 4  (CH3.CO.CO.CH3)  strikes  with  creatin  (but 
not  with  Creatinin)  will  prove  successful  for  colorimetric 
determination  remains  to  be  seen ;  the  results  reported  are 
apparently  not  entirely  equivalent  to  those  obtained  by 
Folin's  method. 

Relation  Between  Creatin  and  Creatinin. — Solution  of 
the  creatin  problem5  has  been  retarded  by  the  fact  that 

/  N(CH3)-CH2    \ 

physiological  relation  between  creatin  J  c(NH)/  j         ) 

V  NH2       COOH/ 

/  N(CH3)-CHA 

and  its  anhydride,  Creatinin     I    c(NH)/  I      ),     has 

V  NH CO  / 

been  repeatedly  denied.  It  is,  of  course,  proper  to  assign  no 
particularly  important  place  in  physiological  chemistry  to 
' '  feelings ' ' ;  but  to  say  the  least  we  cannot  well  do  entirely 
without  them.  In  the  author's  judgment  a  discerning  bio- 
chemical sense  must  necessarily  tell  us  that  two  substances, 
like  creatin  and  Creatinin,  one  of  which  may  be  transformed 

a  F.  G.  Benedict  and  V.  C.  Meyers  ( Wesleyan  Univ. ) ,  Amer.  Jour,  of 
Physiol.,  18,  397,  1907. 

8  In  the  presence  of  sugar,  where  the  method  is  attended  with  certain 
difficulties,  according  to  W.  C.  Rose  (Univ.  of  Pennsylvania),  Jour,  of  Biol. 
Chem.,  12,  73,  1912,  the  creatin  may  he  changed  into  Creatinin  by  heating  with 
phosphoric  acid  in  the  autoclave. 

4G.  S.  Walpole  (Wellcome  Research  Lab.),  Jour,  of  Physiol.,  42,  301,  1911. 

5 Literature  upon  Creatin  Metabolism:  C.  A.  Pekelharing,  Centralbl.  f. 
Stoffweehselkr.,  1909,  No.  8;  A.  Schittenhelm,  Handb.  d.  Biochem.,  //,  535-539, 
1910. 


124  CREATIN  AND  CREATININ 

into  the  other  by  the  simplest  sort  of  chemical  interference 
(boiling  with  acid)  are  bound  to  bear  a  direct  physiological 
relation  to  each  other.  To-day  such  a  relation  may  be 
looked  upon  as  definitely  proved  from  the  works  of  Pekel- 
haring  and  his  school ;  and  we  are  justified  in  assuming  that 
the  urinary  Creatinin  owes  its  origin  to  anhydration  of  the 
creatin  (primarily  appearing  in  the  tissue  protoplasm  of  the 
body  or  introduced  with  meat  food).6  This  anhydration  is 
not  necessarily  always  a  complete  one,  as  greater  or  smaller 
amounts  of  creatin  usually  coexist  with  Creatinin  in  the 
urine.  For  this  reason  in  biological  studies  it  is  never  re- 
garded as  sufficient  to  make  an  estimation  of  Creatinin  alone> 
but  to  deal  with  the  total  amount  of  the  two  substances.  In 
the  urine  of  birds  the  Creatinin  is  of  decidedly  less  impor- 
tance than  creatin.7 

Creatase  and  Creatinase. — Added  difficulty  in  the  study 
of  the  problem  arises  from  the  fact  that  along  with  the 
change  of  creatin  into  Creatinin  (apparently  from  the  influ- 
ence of  anhydrating  ferments)  there  also  occurs  a  decompo- 
sition of  both  substances  in  the  tissues.  Gottlieb  and 
Stangassinger,8  who  are  responsible  for  this  important 
observation,  ascribe  it  to  the  influence  of  special  ferments 
(creatase  and  creatinase).  Arginase  is  not  involved  in  the 
process.9  The  chemical  course  of  this  process  of  decomposi- 
tion, which  is  also  to  be  met  in  excised  living  organs,  is 
unknown.  The  cyclically  formed  Creatinin  is  apparently 
affected  with  more  difficulty  than  the  creatin.  Creatin 
which  has  been  introduced  parenterally  into  the  circula- 
tion of  mammals  is  partly  decomposed  in  the  body  ac- 

«Cf.  E.  P.  Cathcart  (Glasgow),  Jour,  of  Physiol.,  39,  320,  1909;  D.  Noel 
Paton,  ibid.,  39,  485,  1910. 

7  D.  Noel  Paton,  1.  c. 

8  R.  Gottlieb  and  R.  Stangassinger,  Zeitschr.  f .  physiol.  Chem.,  52,  1  1907 ; 
55,  295,  322,  1908. 

9H.  D.  Dakin  (C.  A.  Herter's  Lab.,  New  York),  Jour,  of  Biol.  Chem.,  3, 
435,  1907. 


CREATIN-CREATININ  ELIMINATION 


125 


cording  to  the  studies  of  Pekelharing  and  his  associates,10 
partly  excreted  without  change,  partly  excreted  after  anhy- 
dration  into  Creatinin;  and  according  to  these  writers  the 
liver  is  apparently  of  importance  both  in  the  decomposition 
and  also  in  the  process  of  dehydration.  Besides  this  mode 
of  destruction,  in  experiments  in  which  creatin  or  Creatinin 
has  been  introduced  by  the  mouth  decomposition  may  take 
place  of  either  substance  from  the  agency  of  bacteria  in  the 
intestine ;  so  that  it  is  not  at  all  surprising  in  such  experi- 
ments if  nothing  but  a  fraction  of  the  substances  introduced 
appears  in  the  urine.1  x 

Endogenous  and  Exogenous  Distribution  of  Creatin- 
Creatinin  Elimination. — In  trying  to  recognize  the  precise 
sources  of  the  urinary  creatin  and  Creatinin  reference  to  a 
recent  illuminating  presentation  of  the  subject  by  Lafayette 
Mendel 12  with  the  following  schema  based  thereupon  may 
serve  to  most  quickly  orient  ourselves  upon  the  subject : 


Preformed  creatin 
from  meat  food 


Protein 


Food  Protein        Reserve  Protein         Tissue  Protein 
(Circulating  Protein) 

O  O  Creatin 


Portion  Decomposed 
in  Metabolism 


Urinary 
Creatin 


Urinary 
Creatinin. 


10  C.  A.  Pekelharing  and  C.  J.  C.  Van  Hoogenhuyze,  Zeitschr.  f.  physiol. 
Chem.,  69,  395,  1910;  cf.  also  P.  A.  Levene  and  L.  Kristeller,  Amer.  Jour,  of 
Physiol.,  %k,  44,  1909. 

u  W.  Czernecki  (E.  S'alkowski's  Lab.),  Zeitschr.  f.  physiol.  Chem.,  U,  294, 
1905;  P.  Nawiasky  (M.  Rubner's  Lab.),  Arch.  f.  Hygiene,  66,  239,  1908;  R.  H. 
A.  Plimmer,  M.  Dick  and  C.  C.  Lieb,  Jour,  of  Physiol.,  S9,  112,  1909-10. 

12  L.  B.  Mendel  and  W.  C.  Rose,  Jour,  of  Biol.  Chem.,  10,  249,  1911. 


126  CREATIN  AND  CREATININ 

It  is  apparent  from  this  that  (just  as  we  are  accustomed 
to  recognize  an  endogenous  and  an  exogenous  fraction  of 
the  purin  bodies  in  the  urine)  we  are  in  position  to  make 
an  analogous  differentiation  in  case  of  the  creatin-creatinin 
excretion.  The  possibility  of  increasing  the  proportion  of 
creatin  and  Creatinin  in  the  urine  by  free  intake  of  creatin  in 
meat  food  or  Liebig's  meat  extract  has  been  repeatedly 
observed.  This  exogenous  part  can  readily  be  excluded  by 
starvation  or  by  exhibition  of  food  which  does  not  contain 
creatin.  In  this  connection  the  interesting  fact  has  been 
developed  that  under  such  circumstances  individual  vari- 
ations may  be  observed  and  these  may  remain  constant  for 
a  given  normal  individual  for  as  long  a  time  as  a  year,13 
reminding  one  of  the  observations  of  Bnrian  and  Schur,  who 
were  able  to  establish  a  similar  individual  constancy  in  case 
of  the  endogenous  purins. 

Taking  up  next  the  question  as  to  how  far  we  are  justified 
in  assuming  a  relation  between  the  disintegration  of  tissue 
protein  and  creatin  formation  in  metabolism,  it  may  be 
assumed,  as  indicated  in  the  above  schema,  that  neither  the 
food  protein  nor  the  readily  mobilizable  "circulating" 
protein  forms  a  source  of  creatin  and  its  anhydride, 
Creatinin.  This  is  directly  apparent  from  the  fact  that  the 
excretion  of  creatin-creatinin  does  not  proceed  in  precisely 
parallel  lines  with  the  total  protein  exchange,14  and  more- 
over seems  to  be  fairly  independent  of  the  intake  of  proteid 
food. 

Relation  of  Creatin-Creatinin  Excretion  to  Decomposi- 
tion of  Tissue  Protein. — However,  an  increase  in  the  excre- 
tion of  creatin  and  Creatinin  is  to  be  observed  in  those  condi- 
tions where  (and  here  probably  is  the  kernel  of  the  whole 
problem)   there  is  extensive  decomposition  of  the  tissue 

13  O.  Folin  (Waverley),  Amer.  Jour,  of  Physiol.,  13,  84,  1905;  C.  J.  C.  Van 
Hoogenhuyze  and  H.  Verploegh  (Physiol.  Lab.,  Utrecht),  Zeitschr.  f.  physiol. 
Chem.,  57,  161,  1908;    59,  101,  1909. 

14  J.  Forschbach  and  S.  Weber  (Minkowski's  Clinic,  Greifswald),  Centralbl. 
f.  Physiol,  u.  Pathol,  d.  Stoffw.,  1906,  569. 


DECOMPOSITION  OF  TISSUE  PROTEIN  127 

protein,  as  in  starvation,15  in  fever,16  in  diabetes,17  in  poison- 
ing by  phloridzin  18  and  phosphorus,19  after  being  in  an 
atmosphere  poor  in  oxygen,20  and  after  strenuous  muscular 
exertion.21  It  is  extremely  suggestive  that  this  is  especially 
true  in  the  last  mentioned  condition  if  the  muscular  effort 
is  performed  after  insufficient  nutrition,  at  the  expense  of 
the  part  involved  in  the  exertion.  It  appears  that  work 
does  not  necessarily  induce  increase  of  creatin-creatinin 
elimination  in  well  fed  human  beings  and  animals ;  but  in 
conditions  of  hunger  this  is  quite  apt  to  be  the  result.  In 
phloridzin  diabetes  the  elimination  of  Creatinin  is  particu- 
larly increased  when  there  is  an  insufficiency  of  carbohydrate 
in  the  food.  It  is  a  fact,  too,  that  in  protein  starvation  the 
creatin-creatinin  elimination  can  be  prevented  by  exhibition 
of  carbohydrate  (or  especially  of  fat).22  This  recalls  the 
well-known  antagonism  of  carbohydrates  to  the  elimination 
of  acetone  bodies;  in  both  instances  there  may  be  recog- 
nized the  ability  of  carbohydrates  to  satisfy  the  immediate 
needs  of  the  body,  as  it  were  by  payment  of  available  small 
change,  and  thus  to  avert  the  necessity  of  liquidation  of  its 
fixed  assets.  That  no  direct  relation,  but  merely  a  parallel- 
ism,   exists    between    the    elimination    of    acetone    bodies 

"E.  P.  Cathcart  (Glasgow),  Jour,  of  Physiol.,  39,  311,  1909;  L.  B. 
Mendel  and  W.  C.  Rose  (Yale  Univ.),  Jour,  of  Biol.  Chem.,  10,  255,  1911. 

16  H.  Rietschel,  Jahrb.  f.  Kinderheilk..  61,  621,  1905;  O.  af  Klercker 
(Lund),  Zeitschr.  f.  klin.  Med.,  68,  22,  1909;  A.  Skutetzky  (v.  Jaksch's  Clinic, 
Prague),  Deutsch.  Arch.  f.  klin.  Med.,  103,  423,  1911. 

17  R.  A.  Krause  (Edinburgh),  Quarterly  Jour,  of  Physiol.,  3,  289,  1010; 
R.  A.  Krause  and  W.  Cramer,  Jour,  of  Physiol.,  40,  1,  1910. 

18  E.  P.  Cathcart,  and  M.  R.  Taylor  (Glasgow),  Jour,  of  Physiol.,  41,  276, 
1910. 

19  G.  Lefmann  (Heidelberg),  Zeitschr.  f.  physiol.  Chem.,  57,  476,  1908. 

20  C.  J.  C.  van  Hoogenhuyze  and  H.  Verploegh  ( Pekelharing's  Lab., 
Utrecht),  Zeitschr.  f.  physiol.  Chem.,  41,  101,  1909. 

21  Older  literature  upon  the  Relation  Between  Creatin  and  Muscular  Ac- 
tivity: Liebig,  Sarakow,  Ranke,  Xawrocki,  C.  Voit,  Monari,  Grocco,  Moitessier, 
Gregor;  cf.  O.  v.  Fürth,  Ergebn.  d.  Physiol.,  2,  603-605,  1903. 

32 L.  B.  Mendel  and  W.  C.  Rose  (Yale  Univ.),  Jour,  of  Biol.  Chem.,  10, 
213,  1911. 


128  CREATIN  AND  CREATININ 

(acidosis)  and  that  of  Creatinin23  is  readily  appreciable,  the 
former  process  involving  a  drain  upon  the  fat  deposit,  the 
latter  upon  the  tissue  proteins. 

Muscle  as  the  Source  of  Creatin. — In  harmony  with  the 
hypothesis  of  consumption  of  tissue  protein  in  the  construc- 
tion of  creatin  may  be  offered  the  observation,  made  long 
ago  in  the  laboratory  of  Hoppe-Seyler,  and  recently  con- 
firmed,24 that  in  conditions  of  inanition  the  muscles  are  rich 
in  creatin. 

That  muscle  may  be  the  source  of  creatin  may  be  directly 
inferred  from  the  large  amount  of  this  substance  contained 
in  it.  Marked  increase  of  the  creatin-creatinin  content 
ensues  in  isolated  frog's  muscle  upon  nervous  stimulation 25 ; 
and  the  excised  functionating  mammalian  heart  in  Ringer's 
solution  may  discharge  considerable  quantities  of  creatin 
and  Creatinin  into  the  surrounding  fluid.26  From  recent 
studies  of  Pekelharing  and  his  pupils  the  impression  is  given 
that  tonic  contracture  of  a  muscle  is  more  favorable  than 
the  short  contraction  of  ordinary  muscular  action  to  induce 
a  high  degree  of  cleavage  production  of  creatin.27  With  the 
work  of  Gottlieb  and  his  associates,  the  results  of  which  are 
in  consonance  with  this  view,  and  those  of  Seemann  (cf.  Vol. 
I  of  this  series,  p.  148,  Chemistry  of  the  Tissues)  before  us, 
we  may  well  assume  as  a  working  hypothesis  (in  spite  of  the 
negative  results  of  Mellanby)  that  creatin  can  be  produced 
by  cleavage  from  a  colloid  precursor  in  muscle  tissue  not 
only  by  vital  but  also  under  certain  circumstances  by  post 

23  E.  P.  Cathcart  and  M.  R.  Taylor,  1.  c. 

24  B.  Demant,  Zeitschr.  f.  physiol.  Chem.,  3,  388,  1879;  L.  B.  Mendel  (Yale 
Univ.),  Jour,  of  Biol.  Chem.,  10,  255,  1911. 

26  T.  Graham-Brown  and  E.  P.  Cathcart,  Jour,  of  Physiol.,  37,  XIV,  1908. 
28  S.  Weber  (Minkowski's  Clinic,  Greifswald),  Arch.  f.  exper.  Pathol.,  58, 

93,  1907. 

27  C.  J.  C.  Van  Hoogenhuyze  and  H.  Verploegh,  Zeitschr.  f.  physiol.  Chem., 
1,6,  415,  1905;  C.  J.  C.  Van  Hoogenhuyze,  Jahresber.  f.  Tierchem.,  39,  445,  1909; 
C.  A.  Pekelharing  and  C.  J.  C.  Van  Hoogenhuyze,  ibid.,  64,  262,  1910;  C.  A. 
Pekelharing,  ibid.,  75,  207,  1911. 


TEST  OF  HEPATIC  FUNCTION  129 

mortem  autolytic  processes.28  In  further  course  of  auto- 
lysis the  creatin  undergoes  partial  anhydration  into 
Creatinin;  and  thereafter  both  substances  may  be  decom- 
posed by  fermentation. 

Cleavage  of  Creatin  from  Other  Tissues. — Assuming, 
for  a  time  at  least,  the  formation  of  creatin  in  muscle 
autolysis  as  proven,  the  further  question  presents  itself 
as  to  whether  production  by  autolytic  cleavage  is  limited  to 
the  musculature  or  whether  the  same  possibility  resides  in 
other  tissues  as  well.  Gottlieb  and  Stangassinger  29  (after 
observing  in  experiments  in  which  they  employed  expressed 
tissue  juices,  that,  as  in  case  of  muscle,  so,  too,  in  kidneys  in 
an  early  stage  of  autolysis  there  appears  an  increase  of 
the  creatin  and  Creatinin  present)  have  expressed  the  opin- 
ion, based  upon  perfusion  experiments,  that  probably  "  quite 
a  number  of  different  tissues  are  to  be  considered  as  possible 
sources  of  the  blood  creatin.  The  formation  of  creatin  in 
the  perfused  livers  of  well  nourished  animals  is  apparently 
quite  important.  .  .  .  It  is  therefore  entirely  possible 
that  the  liver  in  lifetime  may  be  an  important  site  of  creatin 
formation."  The  above  statements  bearing  upon  the 
topography  of  creatin  formation  are  unmistakably  very 
meagre.  The  fact  that  many  tissues  contain  creatin,  and, 
too,  that  many  bacteria 30  are  able  to  produce  Creatinin, 
should  perhaps  be  interpreted  as  indicating  that  we  really 
have  here  to  do  with  a  widespread  function  of  living  cells. 

Test  of  Hepatic  Function. — Our  knowledge  of  the  topog- 
raphy of  the  other  phases  of  creatin  metabolism  (anhydra- 
tion of  creatin  into  Creatinin,  and  the  decomposition  of 
both  substances)  is  likewise  by  no  means  satisfactory.     It 

28  F.  Urano  (Hofmeister's  Lab.),  Hofmeister's  Beitr.,  9,  104,  1906;  R. 
Gottlieb  and  R.  Stangassinger,  Zeitschr.  f.  physiol.  Chem.,  52,  1,  1907;  A. 
Rothmann  (Gottlieb's  Lab.),  ibid.,  57,  131,  1908;  J.  S'eeman,  Zeitschr.  f.  Biol., 
55,  322,  1908;    69,  333,  1907;    E.  Mellanby,  Jour,  of  Physiol.,  36,  447,  190S. 

28  R.  Gottlieb  and  R.  Stangassinger,  Zeitschr.  f.  physiol.  Chem.,  55,  322,  336, 
1908. 

so  N,  Antonoff,  Centralbl.  f.  Bakter.,  43,  209,  1907. 

9 


130  CREATIN  AND  CREATININ 

was  hoped  that  the  study  of  creatin  metabolism  would  lead 
to  a  method  of  determining  the  functional  condition  of  the 
liver,  from  the  rather  undefined  idea  that  the  liver  was  the 
site  of  enzymic  anhydration  of  the  creatin.  In  phosphorus 
poisoning,31  and  in  degenerative  processes  involving  the 
hepatic  parenchyma,  especially  in  hepatic  carcinoma,32  it  is 
said  that  urinary  creatin  is  increased,  with  reduction  of 
Creatinin.  However,  exclusion  of  the  liver  from  the  portal 
circulation  does  not  materially  affect  creatin  metabolism.33 
One  of  the  author's  pupils,  H.  Ishihara,34  was  likewise  un- 
able to  detect  any  influence  of  the  kind  in  the  course  of  sub- 
chronic  phosphorus  poisoning  in  dogs ;  and  the  author  feels 
there  is  little  to  be  expected  from  this  point  of  view  as  far  as 
a  clinical  test  of  the  hepatic  function  is  concerned. 

Relation  of  Creatin  Metabolism  to  Processes  in  the 
Female  Sexual  Organs. — The  recognition  of  a  relation  be- 
tween creatin  metabolism  and  the  cyclical  processes  of  the 
female  genital  organs  is  of  decided  interest.  Creatin  ap- 
pears in  the  urine  of  women  in  increased  amount  after 
menstruation,  but  may  be  entirely  absent  in  the  intermen- 
strual period.  It  may  occur  in  the  latter  part  of  pregnancy 
and,  too,  in  the  period  of  involution  of  the  uterus  after  de- 
livery.35 It  would  be  decidedly  gratuitous  to  attempt  to 
explain  these  phenomena  on  the  basis  of  a  lowering  of  the 
anhydrizing  ability  of  the  liver;  there  is  at  least  as  much 
reason  to  suppose  that  they  are  due  to  changes  in  the 
myometrium   itself;    for   that   matter,    however,    the    one 

81  G.  Lefmann,  Zeitschr.  f.  physiol.  Chem.,  57,  468,  1908. 

32  C.  J.  C.  Van  Hoogenhuyze  and  H.  Verploegh,  Zeitschr.  f .  physiol.  Chem., 
58,  161,  1908. 

33  E.  S.  London  and  N.  Bolgarski,  Zeitschr.  f.  physiol.  Chem.,  62,  465,  1909 ; 
C.  Towles,  and  C.  Voegtlin  (Johns  Hopkins  Univ.),  Jour,  of  Biol.  Chem.,  10, 
479,  1912. 

34  H.  Ishihara  (Instit.  of  Physiol.,  Univ.  Vienna),  Biochem.  Zeitschr.,  Ji, 
315,  1912. 

35  R.  A.  Krause  (Edinburgh),  Quarterly  Jour,  of  Physiol.,  4,  293,  1911; 
R.  A.  Krause  and  W.  Cramer,  Jour,  of  Physiol.,  Ifi,  Proc.  of  Phys.  Soc,  XXXIV, 
1911;    J.  R.  Murlin  (New  York),  Amer.  Jour,  of  Physiol.,  28,  422,  1911. 


ORIGIN  OF  CREATIN  FROM  ARGININ  131 

hypothesis  is  as  far  from  proof  as  the  other.  Experiments 
on  the  excised  living  uterus  have,  however,  constantly  indi- 
cated that  the  amount  of  creatin,  in  proportion  to  the  weight 
of  the  uterine  muscle,  increases  with  the  muscular  activity 
which  has  been  in  play.36 

Possible  Origin  of  Creatin  from  Arginin. — It  must  be 
confessed  at  the  last  that  we  really  do  not  know  the  ultimate 
derivation  of  creatin.  Apparently  it  originates  from 
protein.  Even  if  we  actually  had  proved  to  our  satisfaction 
that  it  is  formed  in  the  course  of  tissue  autolysis,  this  would 
not  prove,  however,  that  it  necessarily  originates  from  the 
proteins.  Other  tissue  components,  known  and  unknown, 
might,  with  equal  propriety,  enter  into  question.  If,  how- 
ever, the  graphic  formula  of  creatin  is  examined  and 
compared  with  that  of  arginin, 


CREATIN  ARGININ 

/NH2  /NH2 

C(NH)<  C(NH)< 

XN(CH3)  XNH 

I  \ 

CH2.COOH  CH2 

CH, 


CH2 

CH.NH, 
COOH, 
our  biochemical  sense  suggests  (it  must  be  confessed  that 
even  with  the  best  of  intentions  we  cannot  get  on  without 
something  of  the  sort)  that  a  relation  between  the  substances, 
even  if  not  proved,  is,  a  priori,  extremely  probable.  Prom 
arginin,  which  forms  one  of  the  important  constituents  of 
the  protein  molecule,  by  a  typical  oxidation  there  may  be 

/  ,nh/NH2  \ 

produced  guanidin  acetic  acid  J  ^nh— CH2     ),  which  re- 

^  cooir 

quires  only  a  simple  methyl  binding  for  transformation  into 

36 Rübsamen  and  Gusikoff  (E.  Kehrer's  Clinic,  Berne),  Arch.  f.  Gynäkol., 
95,  461,  1912. 


132  CREATIN  AND  CREATININ 

creatin.  A  whole  series  of  examples  may  be  appealed  to  to 
show  that  the  living  body  actually  is  engaged  in  bringing 
about  such  a  process  of  methylation.  Metabolically  from 
telluric  or  selenic  acid,  as  Franz  Hofmeister  noted,37  tel- 
lurium methide  or  selenium  methide  can  be  formed;   from 


CTT 

pyridin,  I         ,  according  to  His,38  may  be  produced 

HC  1    ),  CH 


methylpyridylammonium hydroxide,  hc'IIch;     from   di- 

N 

/   \ 
CH3         OH 

C   TT 

ethylsulphide,         Ns,   according  to  Neuberg  and  Grosser,39 
diethylmethylsulphinium  hydroxide    /^^Xg/^*13  \      j^  js 


/C2H6V  yCH3\ 

V^Ha7'    \)H/' 


rather  difficult  to  appreciate  precisely  why,  therefore,  we 
should  deny  the  possibility  of  methylation  of  guanidinace- 
tic  acid  in  metabolism.  Even  the  negative  or  varying  results 
of  experiments  intended  to  influence  the  elimination  of  crea- 
tin and  Creatinin  in  the  urine  and  the  amount  of  creatin  in 
the  muscles  by  administration  of  guanidin  acetic  acid  or  of 
proteins  rich  in  arginin40  prove  but  little.  It  is  a  well 
known  fact  that  attempts  are  not  always  successful  to  re- 
produce at  will  the  processes  which  accompany  protein 
decomposition  in  the  living  body  by  experimental  introduc- 
tion of  their  decomposition  products. 

37  P.  Hofmeister,  Arch.  f.  exper.  Pathol.,  SS,  198,  1894. 

38  W.  His,  Arch.  f.  exper.  Pathol.,  22,  253,  1887. 

39  C.  Neuberg  and  Grosser,  2.  Tagung  d.  deutsch,  physiol.  Gesel.,  Cen- 
tralbl.  f.  Physiol.,  19,  316,  1905. 

40  W.  Czernecki  ( S'alkowski's  Lab.),  Zeitschr.  f.  physiol.  Chem.,  kk,  294, 
1905;  M.  Jaffe,  ibid.,  48,  430,  1906;  G.  Dorner  (Jaffe's  Lab.),  ibid.,  52,  225, 
1907;    O.  af  Klercker,  Hofmeister's  Beitr.,  8,  59,  1906;    E.  Mellanby,  1.  c. 


OTHER  URINARY  BASES  133 

OTHER  URINARY  BASES 

M ethyl guanidin;  Dimethylguanidin;  Vitiatin. — Besides 
creatin  and  Creatinin  small  quantities  of  other  bases  closely 
related  to  them  may  be  met  at  times  in  the  nrine.  In  the  Mar- 

NTT 

burg  Physiological  Institute  methyl  guanidin ,  C(NH)/ 

has  been  isolated  from  normal  human  urine  in  its  relatively 
insoluble  picrolonic  acid  combination;  and  in  the  urine  of 
dogs,   after  ingestion  of  meat  extract,   dimethylguanidin, 

/NH2 

C(NH)v     CH3  , 

XN/        has  been  found.      Vitiatin,  with  its  ascribed 

CH3 

/NH— CH2— CHa— N  v 
structural  formula,    C(NH)<  |    XXNH),  (cf.  Vol. 

XNH2  CH3  / 

NH,' 

I  of  this  series,  p.  149,  Chemistry  of  the  Tissues)  has  also 
been  met  in  the  urine.41 

Small  quantities  of  methylpyridin  may  occur,  probably 
produced  from  vegetable  foods ;  pyridin  compounds  are  in- 
troduced into  the  body  with  the  nicotine  of  tobacco  smoke 
and  with  some  of  the  constituents  of  coffee.42 

Novain. — Then,  too,  small  quantities  of  bases  may  appear 
in  the  urine,  having  a  number  of  methyl  groups  linked 
to  nitrogen.  Kutscher 43  encountered  novain  (as  previously 
stated  in  these  lectures,  Vol.  I  of  this  series,  p.  151,  this 
substance   may  be    regarded    as    identical   with    carnitin, 

ca'\  \ 

CH3 — N —  — O    I :  reductonovain  also  occurs,  re- 

CH3/       CHa-CH^CHCOID-CC/ 

41  F.  Kutscher  and  Lohmann,  Zeitschr.  f.  physiol.  Chem.,  48,  422,  1906; 
49,  81,  1906;  W.  Achelis,  ibid.,  50,  10,  1906;  F.  Kutscher,  ibid.,  51,  457,  1907; 
R.  Engeland,  ibid.,  51,  49,  1908. 

42  F.  Kutscher,  1.  c. 
"  F.  Kutscher,  1.  c. 


134  URINARY  BASES 

lated  to  novain  in  the  same  way  as  is  neurin  to  cholin.  These 
bases  characteristically  yield  by  cleavage  trimethylamine 
when  distilled  with  alkali. 

Trimethylamine. — In  connection  with  the  question 
whether  trimethylamine  occurs  as  such  in  the  urine,  Takeda, 
one  of  Kutscher 's  pupils,  has  brought  forward  the  necessity 
of  employing  a  partial  vacuum  distillation  method.  The 
residue  of  the  urinary  distillate  taken  up  in  dilute  hydro- 
chloric acid  is  separated  into  a  fraction  soluble  in  alcohol  and 
one  insoluble  in  alcohol;  and  from  the  latter  the  gold 
chloride  combination  of  trimethylamine  is  obtained.44 

Takeda  found  that  preformed  trimethylamine  does  not 
exist  in  the  urine  of  dogs  and  of  horses,  but  may  sometimes 
be  present  in  human  urine;  it,  however,  always  appears 
when  alkaline  ammoniacal  fermentation  takes  place  in  urine. 

Erdmann  was  unable  to  detect  trimethylamine  in  normal 
fresh  human  urine.  However,  it  has  been  learned  that  if  the 
urine  is  treated  with  concentrated  sulphuric  acid  as  if  for 
Kjeldahl  estimation,  and  the  fluid  alkalinized  after  decolori- 
zation  and  distilled,  alkylamine,  including  trimethylamine, 
passes  over  with  the  ammonia.45 

The  author's  student,  Kinoshita,46  proceeded  as  follows: 
He  distilled  off  under  lowered  pressure  the  volatile  amines 
from  the  urine  in  presence  of  magnesia,  taking  them  up  in  a 
receiver  containing  dilute  hydrochloric  acid.  In  the 
chloride  residue  which  remained  after  evaporation  of  the 
distillate,  consisting  mainly  of  ammonium  chloride  and  a 
small  admixture  of  the  chlorides  of  other  volatile  bases,  the 
amount  of  alkyl  in  nitrogen  combination  was  determined  by 
the  method  of  J.  Herzig  and  H.  Meyer,  and  as  a  conclusion 

44  Takeda  (Physiol.  Instit.,  Marburg),  Pflüger's  Arch.,  129,  82,  1909. 

45  O.  Folin,  C.  C.  Erdmann  (Waverley),  Jour,  of  Biol.  Chem.,  3,  83,  1907; 
8,  41,  57,  1910;    9,  85,  1911. 

40  T.  Kinoshita  (University  Physiol.  Instit.,  Vienna),  Centralbl.  f. 
Physiol.,  2k,  No.  17,  1910. 


ARNOLD'S  REACTION  135 

from  the  preliminary  findings  it  was  held  that  the  alkyl  was 
really  present  in  the  form  of  trimethylamine.  In  conformity 
with  the  above  the  amount  of  trimethylamine  recoverable  by 
distillation  from  normal  fresh  urine  was  found  extremely 
small.  And,  too,  expectation  of  obtaining  larger  amounts 
after  acid  or  alkaline  hydrolysis  was  not  fulfilled.  Somewhat 
larger  amounts  of  the  base  were  found  in  spoiled  urines; 
and  the  largest  proportions  (about  3  to  6  centigrams  in 
the  liter  of  urine)  were  met  in  a  few  urines  which,  with  or 
without  addition  of  toluol,  had  been  standing  for  a  long 
time  at  room  temperature,  from  which  it  must  be  inferred 
that  the  cleavage  production  of  trimethylamine  is  the  result 
of  a  fermentative  process  acting  on  some  "mother  sub- 
stance. ' '  Doubtless  the  physiological  significance  of  the  ap- 
pearance of  trimethylamine  in  urine  has  been  much  over- 
estimated by  the  earlier  investigators.47 

Arnold's  Reaction. — One  more  peculiar  substance  should 
be  mentioned,  which  appears  in  the  urine  particularly  after 
ingestion  of  meat  or  meat  bouillon  and  which  underlies  the 
' '  Arnold  reaction. ' '  Upon  addition  of  sodium  nitroprusside 
and  alkali  a  violet  color  is  assumed,  which  changes  to  blue 
when  acetic  acid  is  added.  The  nature  of  this  reaction  is 
not  known;  and  the  substance  producing  it  is,  to  say  the 
least,  very  fugitive,  disappearing  from  the  urine  in  the 
course  of  a  few  days,  even  if  the  specimen  be  preserved  by 
addition  of  sublimate.  It  has  been  stated  that  the  reaction 
is  a  "typical  meat  reaction,"  but  this  probably  cannot  be 
maintained  as  it  has  also  been  observed  after  use  of  milk, 
cheese  and  eggs.48 

17  C.  Serena  and  A.  Percival,  Jahresber.  f.  Tierchem.,  29,  338,  1890;  F.  de 
Filippi,  Zeitschr.  f.  physiol.  Chem.,  49,  433,  1906. 

48  V.  Arnold  (Lemberg),  Zeitschr.  f.  physiol.  Chem.,  49,  397,  1906;  Th. 
Holobut  (Lemberg),  ibid.,  56,  117,  1908;  X.  Buss,  Inaug.  Dissert.,  Zürich, 
1910,  cited  in  Centralbl.  f.  d.  ges.  Biol.,  11,  No.  1702;  J.  Caretti,  Bull.  Scienze 
Med.,  80,  253,  1909. 


136  URINARY  BASES 

Urinary  Rest-nitrogen. — If  the  nitrogen  of  the  various 
known  urinary  constituents  for  a  given  specimen  be  added 
together  and  the  total  compared  with  the  determined  total 
nitrogen,  will  any  noticeable  difference  be  found?  It  has 
been  shown  that  this  actually  is  the  case.  By  far  the  major 
portion  of  the  nitrogen,  estimated  as  from  87  to  95  per  cent, 
of  the  total  nitrogen  ordinarily  and  in  states  of  full  diet,49  is 
referable  in  man  and  the  mammals  to  urea.  After  calculat- 
ing the  fractions  referable  to  uric  acid,  the  purin  bases  and 
Creatinin,  hippuric  acid  and  ammonia,  there  still  remains  a 
nitrogen  rest  which  in  human  urine  has  been  estimated  at 
from  2.5  to  8.5  per  cent,  by  Donze  and  Lambling,50  at  about 
5  per  cent,  by  Folin,  and  11  per  cent,  of  the  total  nitrogen  by 
Maillard.  These  figures  are  changed  as  soon  as  the  diet 
becomes  abnormal,  the  urea  varying  especially,  falling, 
particularly  where  opportunity  for  an  acidosis  occurs,  with 
corresponding  increase  in  the  ammonia.  0.  Folin  observed  a 
fall  of  the  urea  nitrogen  to  60  per  cent,  of  the  total  nitrogen 
in  as  full  as  possible  restriction  of  proteid  metabolism  by 
means  of  a  starch-cream  diet.  But  even  this  is  probably  far 
from  the  lowest  limit  which  may  be  met.  In  an  insane 
patient,  who  took  almost  no  food,  Folin  found  only  15  per 
cent,  of  the  total  nitrogen  represented  by  the  urea,  and  40  per 
cent,  as  ammonia ; 51  one  would  hesitate  to  give  credence  to 
these  ^  figures  if  they  were  not  published  by  one  who  is  a 
master  of  the  technique  of  urinary  analysis.  It  should  be 
remembered  in  this  connection  that  similar  perverse  metab- 
olism proportions  have  been  observed  in  the  hibernating 
marmot  (v.  supra.,  p.  117),  and  have  been  described  as  an 
enormous  increase  in  the  aminoacids  at  the  expense  of  the 
urea. 

49  Cf.  B.  Schöndorff,  Pflüger's  Arch.,  117,  275,  1907. 

60  G.  Donze  and  E.  Lambling,  Jour,  de  Physiol.,  5,  225,  1903;  O.  Folin, 
Amer.  Jour,  of  Physiol.,  13,  45,  1905;  L.  C.  Maillard,  Jour,  de  Physiol.,  10, 
1017,  1908. 

61  O.  Folin,  1.  c. 


FRACTIONATION  OF  THE  OXYPROTEIC  ACIDS     137 
OXYPROTEIC  ACIDS 

It  would  seem  that  the  bulk  of  the  "non  dose"  in  the 
urine,  the  undetermined  nitrogen  rest,  is  to  be  referred  to 
the  group  of  the  oxyproteic  acids.  These  substances  have 
been  dealt  with  in  a  previous  lecture  in  connection  with  the 
subject  of  the  elimination  of  the  residual  material  of  pro- 
tein metabolism  in  cancerous  affections  (Vol.  I  of  this 
series,  pp.  547-551,  The  Chemistry  of  the  Tissues).  The 
oxyproteic  acids,  discovered  in  the  urine  in  1897  by  S. 
Bondzynski  and  R.  Gottlieb,52  constitute  a  group  of  protein 
derivatives  containing  both  nitrogen  and  sulphur,  and  ap- 
parently of  high  molecular  structure ;  they  seem  to  be  char- 
acterized by  an  acid  nature,  the  solubility  in  water  and 
insolubility  in  alcohol  of  their  baryta  salts,  and  by  their 
precipitation  by  mercuric  acetate  in  weakly  alkaline  reac- 
tion. In  general  they  no  longer  retain  the  character  of 
Polypeptids,  failing  to  give  the  biuret  reaction,  and  not  being 
precipitable,  as  are  other  protein  derivatives  of  high  molec- 
ular structure,  by  phosphotungstic  acid  in  the  presence  of 
excess  of  mineral  acid. 

Fractionation  of  the  Oxyproteic  Acids. — The  investiga- 
tions of  Bondzynski  and  his  collaborators  53  indicated  that 
separation  of  these  acids  is  possible  by  precipitation  as  salts 
of  the  heavy  metals,  and  in  fact  led  to  the  diff erentiation  of 
alloxyproteic  acid  (precipitated  by  acetate  of  lead),  ant  oxy- 
proteic acid  (precipitated  by  mercuric  acetate  in  acid  re- 
actions) and  oxyproteic  acid  (precipitated  by  the  same  in 
neutral  or  weakly  alkaline  reaction).  These  Polish  investi- 
gators are  also  to  be  credited  with  the  important  determina- 
tion that  the    autoxyproteic  fraction  includes  the  yellow 

M  S.  Bondzynski  and  R.  Gottlieb,  Centralbl.  f.  d.  med.  Wiss.,  1897,  No.  33. 

63  S.  Bondzynski  and  K.  Panek,  Ber.  d.  deutsch,  ehem.  Ges.,  85,  2959,  1903; 
S.  Bondzynski,  S.  Dombrowski,  K.  Panek,  Zeitschr.  f.  physiol.  Chem.,  Jf6,  83, 
1905;  S.  Dombrowski,  ibid.,  5>h  188,  1907,  Bull,  de  l'Acad.  de  Cracovie;  CI.  des 
Sciences  Math,  et  Natur.,  October,  1907;  J.  Browinski  and  S.  Dombrowski, 
Jour,  de  Physiol.,  10,  819,  1908;  W.  Gawinski,  Zeitschr.  f.  physiol.  Chem.,  58, 
458,  1909;    S.  Bondzynski,  Kosmos,  35,  680,  1910. 


138 


OXYPROTEIC  ACIDS 


urinary  coloring  matter,  urochrome.  Moritz  Weiss  54  has 
shown  in  the  course  of  his  investigations  (partly  carried  out 
in  the  Vienna  Physiological  Institute)  that  urochrome  is 
produced  from  a  chromogen,  urochromogen,  which  is  like- 
wise an  oxyproteic  acid.  This  chromogen  is  characterized 
by  two  striking  peculiarities,  viz.,  by  its  ability  to  pass  over 
into  urochrome  upon  oxidation  (a  faintly  tinted  yellowish- 
green  solution  assuming  an  intense  yellow  color  when  per- 
manganate of  potassium  is  added  drop  by  drop),  and  by  the 
interesting  fact  that  it  is  the  particular  substance  involved 
in  Ehrlich 's  curious  diazo-reaction.  Very  shortly  after  the 
Polish  authors  happened  upon  the  fact  that  autoxyproteic 
acid  will  give  the  well  known  color  reaction  with  the  neces- 
sary diazo-reagents  the  relation  between  urochromogen  and 
the  diazo-reaction  was  determined  by  Weiss. 

It  is  therefore  apparent  that  we  are  dealing  with  a  de- 
cidedly confusing  group  of  phenomena.  In  the  hope,  how- 
ever, of  simplifying  the  current  status  of  proteic  acid 
fractionation,  the  following  schema  is  presented : 55 


PROTEIC    ACID    FRACTION 

(The  group  of  substances  which  form  baryta  salts  which 
are  soluble  in  water,  but  precipitated  by  alcohol.) 


Alloxyproteic 

Acid  Fraction 

(precipitated  by 

acetate  of  lead) 


Autoxyproteic  Acid 
Fraction  (precipi- 
tated by  mercuric 
acetate  in  weakly 
acid  reaction) 


Dombrowski's 
Urochrome 


Urochromogen 

.(transformed  by  oxidation 

into  true  urochrome) 


Oxyproteic  Acid 
Fraction  (precipi- 
tated by  mercuric 

acetate  in  soda- 
alkaline  reaction) 


Colorless 

Alloxyproteic 

Acid. 


M  M.  Weiss  (Alland  Hosp.) ,  Wiener  klin.  Wochenschr.,  1907,  No.  31 ;  Beitr. 
z.  Klinik  der  Tuberculose,  8,  117,  1907;  Biochem.  Zeitschr.,  21,  175,  1910;  30, 
333,  1911,  under  direction  of  O.  v.  Fürth,  Physiol.  Instit.  Vienna;  Med.  Klinik, 
1910,  No.  92;   Miinchener  med.  Wochenschr.,  1911,  No.  25. 

MM.  Weiss,  Biochem.  Zeitschr.,  30,  338,  1911. 


PROTEIC  ACID  FRACTION  139 

The  alloxyproteic  acid  fraction  apparently  contains  at 
times  four  substances:  Dombrowski 's  urochrome  (recogniz- 
able by  its  precipitation  by  neutral  lead  acetate  and  by 
copper  acetate,  and  the  insolubility  of  its  lead  salt  in  dilute 
acetic  acid),  true  urochrome  of  Weiss  and  the  colorless  allo- 
xyproteic acid  of  the  Polish  writers  True  urochrome,  the 
normal  yellow  coloring  matter  of  urine,  is  not  the  same  as 
Dombrowski 's  urochrome,  and  may  be  differentiated  from 
the  latter  by  the  solubility  of  its  lead  salt  in  dilute  acetic  acid. 
In  addition  urochromogen,  occurring  in  pathological  urines, 
is  found  for  the  most  part  in  this  fraction  (careful  precipita- 
tion avoiding  excess  of  lead  acetate) ;  but  sometimes,  it  is 
true,  it  is  met  in  the  autoxyproteic  acid  fraction. 

Weiss  56  has  devised  a  method  by  which  it  is  possible  to 
estimate  by  comparative  colorimetry  the  amount  of 
urochrome  and  urochromogen  in  a  urine  with  great  exact- 
ness. The  urine  is  first  freed  of  other  coloring  materials  by 
saturation  with  ammonium  sulphate  (urobilin,  hsematopor- 
phyrin  and  uroerythrin) ;  and  the  color  of  the  filtrate  is  then 
compared  by  means  of  a  Dubosq  colorimeter  with  a  true 
yellow  solution  of  known  content.  If  urochromogen  is  pres- 
ent along  with  urochrome  a  dilute  solution  of  permanganate 
is  cautiously  added  as  long  as  increase  in  the  yellow  color 
can  be  clearly  recognized  or  until  the  Ehrlich 's  diazo-reac- 
tion,  if  at  first  present,  begins  to  fail ;  thereafter  the  process 
is  as  above.  The  difference  between  the  quantities  of  uro- 
chrome obtained  before  and  after  the  full  oxidation  repre- 
sents the  quantity  of  urochromogen  present  in  the  specimen. 
In  examining  urines  with  positive  diazo-reactions  there  is 
always  to  be  noted  a  direct  proportion  between  the  intensity 
of  the  diazo-reaction  and  the  amount  of  urochromogen  in  the 
urine.  The  technical  simplicity  and  the  sensitiveness  of  the 
urochromogen  reaction  with  permanganate  makes  it  possible 
to  substitute  the  diazo-reaction  by  the  former. 

50  M.  Weiss,  Biochem.  Zeitschr.,  30,  345,  1911. 


140  OXYPROTEIC  ACIDS 

Chemical  Position  of  Urochrome. — It  is  at  present  not 
advisable  to  say  more  in  reference  to  the  chemical  classi- 
fication of  urochrome,  the  urinary  coloring  matter  which 
is  mainly  responsible  for  the  yellow  color  of  normal  urine, 
than  that  we  are  dealing  with  one  of  the  substances  in- 
cluded in  the  group  of  protein  residual  matter  which 
from  its  characteristics  of  solubility  and  precipitability 
should  be  classed  among  the  oxyproteic  acids.  There  is  a 
contradiction  in  the  matter  of  its  sulphur  content  between 
the  statements  of  the  above-named  Polish  authors,who  found 
the  coloring  material  to  contain  sulphur,  and  the  results  ob- 
tained in  Hofmeister 's  laboratory.57  The  latter  indicate 
that  the  yellow  material,  which  can  be  separated  from  the 
urine  by  animal  charcoal  and  can  subsequently  be  freed  from 
the  latter  by  glacial  acetic  acid  (known  as  "uroipyrryV' 
because  of  the  large  proportion  of  pyrrol  left  when  it  is 
subjected  to  dry  distillation),  does  not  contain  any  sulphur. 
It  may  be  thought  that  this  contradiction  may  be  explained 
on  the  supposition  that  the  urochrome,  which  has  its  sulphur 
bound  so  loosely  in  the  molecular  structure  that  sulphuretted 
hydrogen  separates,  even  without  heating,  when  it  is  acted 
upon  by  alkali,58  may  likewise  undergo  cleavage  in  the 
course  of  the  above  process  of  demonstration  with  loss  of  its 
sulphur ;  but  this  has  not  been  proven.  There  may  possibly 
be  a  close  relation  between  such  a  sulphur  partition  and  the 
peculiar  reduction  power  of  urochrome  which  can  be  directly 
estimated  by  titration  by  separation  of  iodine  from  iodic 
acid.59  The  suggestion  that  urochrome  owes  its  coloring  to 
one  of  the  cyclic  groups  of  the  protein  molecule  included  in 
some  form  in  its  structure  (or  a  transformation  product  of 
such  a  substance)  is  not  improbable.  There  is  not  the  least 
foundation,    however,    for    assuming    a   relation    between 

57  H.  Hohlweg,  K.  E.  Salomonsen,  S.  Mancini  (Lab.  of  Physiol.  Chem., 
Strassburg),  Biochem.  Zeitschr.,  IS,  199,  205,  208,  1908. 

68  S.  Bondzynski,  S.  Dombrowski  and  K.  Panek,  Zeit9chr.  f.  physiol.  Chem., 
46,  83,  1905;    S.  Dombrowski,  ibid.,  62,  358,  1909. 

50  J.  Browinski  and  S.  Dombrowski,  Jour,  de  Physiol.,  10,  819,  1908. 


UROCHROME  141 

urochrome  and  hamiatin  and  urobilin.  Direct  evidence  of 
the  cyclic  nature  of  urochrome  may  perhaps  be  seen  in  the 
striking  diazo-reaction  of  urochromogen.  (A  color  reaction, 
less  brilliant  however,  is  given  by  the  diazo-compounds  with 
formed  urochrome;  it  corresponds  closely  with  the  diazo- 
reaction  of  the  normal  urine.60)  The  fact  that  when  uro- 
chrome is  boiled  with  hydrochloric  acid  melanin-like  prod- 
ucts ("uromelanin")  may  be  formed61  is,  if  the  author  is 
correct  in  his  previous  statements  as  to  the  nature  of 
melanin  production  (v.  Vol.  I  of  this  series,  p.  526,  et  seq.. 
Chemistry  of  the  Tissues),  certainly  not  contradictory  of  a 
cyclic  character  of  urochrome.  It  suggests,  too,  that  certain 
ring-form  groups  in  the  protein-molecule  escape  complete 
dissociation  in  the  course  of  metabolism  and  may  finally 
appear  as  urinary  coloring  materials.  In  the  author's 
laboratory  there  are  in  course  at  present  certain  experiments 
bearing  upon  a  possible  part  taken  by  histidin  in  the  con- 
struction of  urochrome ;  an  idea  suggested  by  the  fact  that 
this  compound  is  distinguished  among  the  molecular  cleav- 
age products  (as  also  tyrosine)  by  responding  to  the  diazo- 
reaction. 

True  Urochrome  and  Dombrowski's  Urochrome. — The 
marked  tendency  to  undergo  decomposition  shown  by 
the  yellow  coloring  substance  of  the  urine,  is,  moreover, 
the  cause  of  the  differences  of  opinion  obtaining  between 
M.  Weiss  and  the  Polish  authors  with  reference  to  it.  While 
the  latter  authors  look  upon  the  urochrome  discovered  by 
themselves  as  the  peculiar  urinary  coloring  matter,  Weiss,  as 
stated,  differentiates  between  true  urochrome  and  the  uro- 
chrome of  Dombrowski.  The  impression  is  that  this  latter 
product,  which  is  isolated  from  urine  by  precipitating  it  by 

60  K.  Feri  (Chvostek's  Clinic,  Vienna)  recommends  substitution  of  the 
Ehrlich  reagent  by  azophen  red,  that  is,  paranitrodiazobenzolsulphate 
(NO-2.0Ä  —  N  =  N  —  )2S'04;  Wiener  klin.  Wochenschr.,  1912,  No.  24. 

61  J.  Dombrowski,  Zeitschr.  f.  physiol.  Chem.,  5Jf,  188,  1907;    62,  358,  1909. 


142  OXYPROTEIC  ACIDS 

means  of  copper  acetate,  with  subsequent  dissociation  of  the 
copper  compound  by  sulphuretted  hydrogen,  is  nothing  but 
an  oxydation  transformation  product  of  the  true  urochrome. 
Browinski  and  Dombrowski 62  in  their  most  recent  publica- 
tion with  special  stress  suggest  "that  urochrome  is  an  un- 
usually easily  decomposable  compound  and  readily  under- 
goes oxidation.  Its  precipitation  from  the  urine  and  from 
pure  solutions  by  means  of  cupric  acetate  is  due  to  the  forma- 
tion of  a  cuprous  compound  which  is  soluble  in  water;  and 
can  occur  only  with  reduction  of  the  copper  acetate.  The  pre- 
cipitation is  therefore  incomplete,  because  necessarily  the 
combination  is  formed  with  oxidation  of  a  portion  of  the 
urochrome. ' '  Thus  far  it  is  possible  to  agree  with  the  Polish 
authors.  But  with  their  further  statement  the  author's 
views  become  directly  opposed :  "The  oxidation  product  (of 
the  urinary  coloring  matter)  which  remains  in  solution  im- 
parts the  faint  yellow  tint  to  the  filtrates  of  copper  precipita- 
tion peculiar  to  them. ' '  According  to  this  the  substance  in  the 
filtrate  would  be  an  insignificant  remnant  of  the  true  urinary 
coloring  matter  which  has  escaped  precipitation  and  has 
undergone  oxidation.  Actually,  however,  as  Weiss  has 
shown  in  his  colorimetric  estimations,63  the  opposite  is  the 
case.  If  Dombrowski 's  urochrome  (a  sallow  brownish 
yellow  coloring  substance)  be  removed,  by  far  the  greater 
part  of  the  coloring  matter  remains  in  the  filtrate,  which 
shows  the  characteristic  pure  tint  (yellow  with  a  greenish 
cast)  of  the  former  [true  urochrome].  Any  unprejudiced 
person  must  grant  that  when  one  knows  that  a  given  sub- 
stance is  very  ready  to  undergo  oxidation  there  is  little 
propriety  in  using  an  oxidizing  agent  like  copper  acetate  in 
isolating  it.  If,  however,  such  an  agent  is  employed  and, 
too,  if  it  has  been  clearly  proved  that  oxidation  has  actually 

62  J.   Browinski   and   S.   Dombrowski    (Instit.   of   Med.   Chem.,   Lemberg), 
Zeitschr.  f.  physiol.  Chem.,  77,  105,  1912. 

63  M.  Weiss,  Biochem.  Zeitschr.,  SO,  340,  1911. 


QUANTITATIVE  DETERMINATION  143 

been  effected  in  the  course  of  demonstration,  it  may  un- 
doubtedly be  said  that  nothing  but  an  oxidation  product  can 
be  expected  as  the  result. 

It  may  be,  too,  that  a  portion  of  the  true  urochrome  may 
undergo  spontaneous  decomposition  in  the  urine  with  forma- 
tion of  its  oxidation  product.  In  any  case  we  must  regard, 
not  Dombrowski's  urochrome,  but  Weiss 's  so-called  "true 
urochrome ' '  as  the  native  urinary  yellow  coloring  material. 
The  attempt  of  the  authors  indicated  to  introduce  a  polemic 
spice  in  their  latest  publication  can  have  not  the  least  influ- 
ence upon  the  actual  fact. 

Quantitative  Determination  of  Oxyproteic  Acids. — 
Our  appreciation  of  the  physiological  role  and  signifi- 
cance of  the  various  substances  of  the  group  of  oxyproteic 
acids  is  of  slow  development.  The  reason  for  this  is  mainly 
that  as  yet  we  are  unable  to  overcome  the  technical  difficul- 
ties attending  a  quantitative  determination  of  these  sub- 
stances. In  discussing  the  elimination  of  the  oxyproteic  acids 
and  of  neutral  sulphur  in  cancerous  disease  (v.  Vol.  I  of  this 
series,  pp.  547-551,  Chemistry  of  the  Tissues)  this  fact  was 
fully  presented.  Recently  objection  has  been  raised  by  F. 
Erben 64  to  the  method  of  Ginsburg C5  for  estimation  of  the 
oxyproteic  fraction  in  urine,  that  besides  the  oxyproteic 
acids  practically  all  the  aminoacids  are  thrown  down.  There 
is  something,  however,  against  the  correctness  of  this  charge 
in  the  fact  that  Ginsburg  has  been  unable  to  find  more  than 
minute  amounts  of  aminoacid  nitrogen  in  his  oxyproteic  acid 
fraction  both  by  formol  titration  and,  too,  by  Van  Slyke's 
method 66  (v.  Vol.  I  of  this  series,  p.  18,  Chemistry  of  the 
Tissues).  Although  Erben  summarily  characterizes  Gins- 
burg's  method  as  "useless,"  it  should  be  observed  that  the 
method,  although  (as  already  stated,  v.  Vol.  I  of  this  series, 

64  F.  Erben  (Vienna),  Internat.  Beitr.  z.  Pathol,  u.  Ther.  d.  Ernährungs- 
störungen, 2,  252,  1911. 

65  W.  Ginsburg  (Univers.  Physiol.  Instit.,  Vienna),  Hofmeister's  Beitr., 
10,  411,  1907. 

68  Personal  communication  from  W.  Ginsburg,  Halle  a.  d.  Saale. 


144  OXYPROTEIC  ACIDS 

p.  548,  Chemistry  of  the  Tissues)  far  from  an  ideally  exact 
mode  of  determination,  is  still  undoubtedly  of  greater  scope 
than  that  of  Erben,  who  sought  no  more  than  the  autoxy- 
proteic  acids  (by  precipitation  of  the  baryta  syrup  by 
mercuric  acetate  after  faint  acidulation  with  acetic  acid). 
This  mode  of  separation  must  be  regarded  as  largely  open 
to  the  personal  equation, — if  for  no  other  reason  because,  as 
is  well  known,  a  part  of  the  mercurial  salts  of  the  oxyproteic 
acids  is  soluble  in  a  greater  surplus  of  acetic  acid.  On  the 
other  hand  it  should  be  acknowledged  that  it  would  be  a  good 
thing  if  a  modification  of  the  Ginsburg  method  were  worked 
out  by  ascertaining  the  possible  admixture  of  urea  and  of 
aminoacids  in  the  fraction  of  oxyproteic  acids,  and  making 
correction  therefor. 

Elimination  of  Oxyproteic  Acids  in  Normal  and  Patho- 
logical Conditions. — With  this  in  view  it  is  best  to  state  only 
in  a  provisional  way  that  the  quantity  of  oxyproteic  acid  in 
normal  urine  represents  from  3  to  7  per  cent,  of  the  total 
nitrogen  in  case  of  adults,67  and  10  per  cent,  in  infants.68 

Probably  the  oxyproteic  acids  in  the  "rest  nitrogen"  of 
the  blood  are  in  greater  proportion  than  they  are  in  the 
urinary  rest  nitrogen  (it  is  said  that  40  per  cent,  of  the  rest 
nitrogen  of  the  blood  serum  is  here  included) ;  and  it  is 
probable  that  a  part  of  the  hsemic  oxyproteic  acids  may 
be  oxidized  before  they  reach  the  kidney  for  elimination.69 

In  disease  an  increased  elimination  of  substances  be- 
longing to  the  group  of  oxyproteic  acids  is  usually  met  in 
cases  in  which  an  increased  decomposition  of  cellular  protein 
is  proceeding  under  the  influence  of  toxic  metabolic  disturb- 
ances.    This  may  be  expected  in  phosphorus  poisoning,  in 

67  W.  Ginsburg,  1.  c;  W.  Gawinski  (Instit.  of  Med.  Chem.,  Lemberg), 
Zeitschr.  f.  physiol.  Chem.,  58,  454,  1909. 

68  S.  Simon  ( Children's  Clinic,  Univ.  Munich ) ,  Zeitschr.  f .  Kinderheilk., 
2,  1,  1911. 

09  J.  Browinski  (Instit.  Med.  Chem.,  Lemberg),  Zeitschr.  f.  physiol.  Chem., 
58,  134,  1908;  W.  Czernecki,  Bull,  de  l'Acad.  de  Cracovie,  1910,  abst.  in 
Jahresber.  f.  Tierchem.,  40,  189,  1910;    cf.  also  ibid.,  39,  820,  1909. 


ELIMINATION  OF  OXYPROTEIC  ACIDS  145 

febrile  infectious  diseases,  hepatic  affections,  the  cachexia  of 
cancer  and  in  the  later  stages  of  tuberculosis.  In  any  such 
condition  an  increased  excretion  of  oxyproteic  acids  may  be 
told  from  the  increase  in  the  elimination  of  neutral  sulphur,70 
which,  as  previously  pointed  out  (v.  Vol.  I  of  this  series,  pp. 
548-550,  Chemistry  of  the  Tissues),  may  serve  as  an  index 
for  the  former.  The  degree  of  complexity  of  the  subject 
may,  however,  be  inferred  from  the  fact  that,  according  to 
circumstances,  now  one,  now  another  fraction  of  the  oxy- 
proteic acids  may  predominate  in  a  given  case.  Thus  in 
tuberculosis  a  much  greater  amount  of  urochromogen  is 
excreted  than  in  cancerous  cachexias.  It  is  a  well-known 
fact  that  a  practical  significance  is  ascribed  to  the  appear- 
ance and  disappearance  of  the  Ehrlich  diazo-reaction  (now 
known  to  be  referable  to  urochromogen)  in  the  matter  of 
prognosis  of  the  course  of  tuberculosis.71 

In  considering  the  diazo-reaction 72  it  should  be  observed 
that  besides  urochromogen  other  substances  may  occur  in 
the  urine  which  yield  color  reactions  with  the  diazo-bodies, 
as,  according  to  Clemens,  tyrosin  (OH.C6H4.CH2.CH(NH2). 
COOH)  and  p-oxyphenylpropionic  acid  (OH.C6H4.CH2.CH2. 
COOH)  and  p-oxyphenylacetic  acid  (OH.C6H4.CH2.COOH). 
Kutscher  and  Engeland  state  that  even  in  normal  urine  after 
removal  of  the  aromatic  oxyacids  by  ether  certain  bodies 
may  remain  which  form  red  products  with  diazo-benzol- 
sulphurous  acid  when  in  an  alkaline  soda  solution.     This 

N— c 
reaction  apparently  is  peculiar  to  the  imidazol  nuclei,    c    c , 

N 

70  Cf.  M.  Halpern,  Centralbl.  f.  d.  ges.  Biol.,  11,  No.  2547,  1911;  E.  Salkow- 
ski,  Biochem.  Zeitschr.,  82,  356,  1911;  cf.  M.  Weiss,  Münchener  med. 
Wochenschr.,  1911,  No.  25. 

71  F.  Kutscher,  Sitzungsber.  d.  Ges.  z.  Bef.  d.  ges.  Naturw.,  Marburg,  4,  83, 
1908;  abst.  in  Centralbl.  f.  Physiol.,  22,  516,  1908;  R.  Engeland  (Physiol. 
Instit.,  Marburg),  Münchener  med.  Wochenschr.,  1908,  1643;  M.  Weiss  and 
A.  Weiss,  Wiener  klin.  Wochenschr.,  1912,  No.  31. 

72  Literature  upon  the  Diazo-reaction  in  Urine :  P.  Clemens  ( Bäumler's 
Clinic,  Freiburg),  Deutsch.  Arch.  f.  klin.  Med.,  63,  74,  1899. 

10 


146  OXYPROTEIC  ACIDS 

which  may  be  found  in  the  urine  in  the  form  of  imidazol- 

CH.NHv 

II  >CH 

C— N    " 

aminopropionic  acid  (histidin),  CH2  ,  and  of  imidazol- 

CH.NH2 

COOH 
CH-NHV 
B  >CH 

C N^ 

aminoacetic  acid,  |  .    It  is  said  that  the  puzzling 

CH.NH2 


"urocaninic  acid"  of  dogs'  urine  is  also  an  imidazol  deriva- 


COOH. 
acid' 

CH-NHV 

II  >CH 

C N^ 

£jve    CH  ,   obtainable  from  histidin  by  ammoniacal 

CH 

I 

COOH 
cleavage.73 

Other  High-molecular  Residual  Substances. — In  addi- 
tion to  the  oxyproteic  acids  there  are  other  high-molecular 
metabolic  residual  substances  of  various  kinds  in  the  urine, 
about  which  we  know  practically  nothing.  E.  Abder- 
halden and  F.  Pregl,74  after  freeing  an  alcoholic  extract 
of  urine  of  urea  and  other  easily  diffusible  materials  by 
dialysis,  obtained  a  mixture  of  substances  which  contained 
no  free  aminoacids  but  after  acid  hydrolysis  yielded  a  num- 
ber of  typical  protein  cleavage  products.  It  is  impossible 
at  the  present  to  decide  the  extent  to  which  these  substances 
are  related  with  the  oxyproteic  acids  (which  unquestionably 
hydrolytically  yield  aminoacids75)  or  with  typical  Poly- 
peptids. It  seems  that  they  may  be  met  in  small  amount  in 
normal  urine  and  somewhat  more  in  disease,  as  in  cancer 

78  A.  Hunter  (Cornell  Univ.),  Jour,  of  Biol.  Chem.,  11,  537,  1912. 
74  E.  Abderhalden  and  F.  Pregl,  Zeitschr.  f.  physiol.  Chem.,  46,  19,  1905. 
76  W.  Ginsburg,  Hofmeister's  Beitr.,  10,  441,  1907;    J.  BrowinBki  and  S. 
Dombrowski  (Lemberg),  Zeitschr.  f.  physiol.  Chem.,  77,  92,  1912. 


HIGH-MOLECULAR  RESIDUAL  SUBSTANCES        147 

and  hepatic  affections  (v.  Vol.  I  of  this  series,  p.  550,  Chem- 
istry of  the  Tissues).  The  chemical  position  of  the  urinary 
constituent  known  as  "uroferric  acid,"  isolated  by  Sieg- 
fried's iron-peptone  method,  is  at  present  indefinable 76 ;  and 
the  same  may  be  said  of  a  substance  obtained  by  P.  Häri 77 
by  precipitation  by  phosphotungstic  acid,  and  the  urinary 
colloids  of  Salkowski  (v.  Vol.  I  of  this  series,  p.  550r  Chem- 
istry of  the  Tissues)  precipitable  by  salts  of  the  heavy  metals 
and  insoluble  in  alcohol.  But  it  would  be  a  mistake  to 
assume  that  all  nitrogenous  colloids  of  the  urine  are  of  the 
nature  of  high-molecular  protein  derivatives.  Investiga- 
tions in  the  laboratory  of  F.  Hofmeister  indicate  on  the 
contrary  that  among  the  nondialysable  urinary  constituents 
(which  can  be  quantitatively  estimated  by  diffusion  methods 
employing  very  fine  fibre  capsules),  we  may  meet  even  such 
materials  as  chondroitin-sulphuric  acid  (Vol.  I  of  this  series, 
p.  281,  Chemistry  of  the  Tissues)  or  nucleinic  acid  as  im- 
portant compounds ;  their  quantity  may  be  found  increased 
in  renal  diseases,  in  eclampsia  and  in  various  febrile  states 
(pneumonia).78 

It  will  probably  be  a  long  time  before  the  misty  atmos- 
phere at  present  enveloping  these  subjects,  and  in  fact  cover- 
ing them  as  in  thick  clouds,  will  be  dissipated  by  the  sun. 
However,  even  here  there  is  beginning  to  be  a  little  more 
light. 

76  O.  Thiele,  H.  Liebermann  (Siegfried's  Lab.,  Leipzig),  Zeitschr.  f.  physiol. 
Chem.,  31,  251,  1903;   52,  129,  1907. 

"P.  Häri  (Budapesth),  Zeitscbr.  f.  pbysiol.  Chem.,  46,  1,  1905. 

78  K.  Sasaki,  Hofmeister's  Beitr.,  9,  386,  1907 ;  M.  Savarg,  ibid.,  9,  401 ;  11, 
71,  1907;  Ch.  Pons,  ibid.,  9,  393,  1907;  U.  Ebbecke,  Biochem.  Zeitschr.,  12, 
485,  1908;    all  from  the  laboratory  of  F.  Hofmeister,  Strassburg. 


CHAPTER  VII 
PHYSIOLOGY  OF  PURIN  METABOLISM 

Having  in  the  last  several  lectures  dealt  with  the  nitrog- 
enous end-products  of  protein  metabolism,  we  may  next 
take  up  the  difficult  subject  of  purin  metabolism.  First, 
however,  it  should  be  said  that  the  general  mass  of  observa- 
tions bearing  upon  this  phase  of  our  subject  is  so  huge  that 
no  honest  man,  even  if  he  has  busied  himself  with  nothing 
else  for  years,  dare  feel  that  he  has  reached  the  bottom  facts- 
and  become  thoroughly  conversant  therewith.  The  author 
would  be  presumptuous,  moreover,  being  himself  not  con- 
tinuously engaged  in  this  field,  but  concerned  rather  with 
the  single  purpose  of  tracing  the  general  subject,  to  attempt 
to  surround  himself  here  with  dogmatic  assertions.  The 
purpose  of  these  lectures  does  not  go  beyond  the  arrange- 
ment and  presentation  of  a  picture  of  this  world  of  phe- 
nomena so  far  as  the  writer  has  from  honest  study  come  to 
understand  and  appreciate  them ;  and  it  should  not  be  for- 
gotten at  any  time  that  this  picture  may  for  other  eyes  have 
a  very  different  aspect.  In  the  end  every  man  has  a  right  to 
use  his  own  eyes  in  inspecting  the  things  about  him ;  only  he 
should  realize  that  his  impressions  in  such  case  are  essen- 
tially subjective  ones.     So  much  in  introduction. 

Exogenous  and  Endogenous  Formation  of  Uric  Acid. — 
The  first  question  to  occupy  us  is — what  do  we  know  of 
the  origin  of  uric  acid  in  the  mammalian  body  I 

In  precise  answer  it  might  be  replied :  it  originates  from 
the  free  nuclein  bases  and  the  nuclein  bases  fixed  in  the  molec- 
ular structure  of  nucleinic  acids.  These  are  in  part  intro- 
duced into  the  living  body  with  food  (exogenous  fraction) 
and  in  part  are  freed  by  nuclear  disintegration  or  other 
processes  within  the  living  organism  from  its  molecular  com- 
binations of  which  they  are  structurally  a  part  (endogenous 
fraction). 

148 


CONVERSION  OF  ADENIN  INTO  URIC  ACID       149 

The  recognition  of  this  relation  had  its  beginning  in  the 
classical  studies  of  Horbaczewski  in  1889  upon  the  formation 
of  uric  acid  in  the  splenic  pulp ;  and  slowly  crystallized  into 
its  present  form  from  a  great  number  of  investigations, 
among  which  those  of  Kossel  and  his  school,  and  of  W. 
Spitzer,  H.  Wiener,  A.  Schittenhelm,  N.  Jones,  R.  Burian, 
L.  B.  Mendel  and  their  collaborators  stand  out  prominently.1 

Conversion  of  Adenin  and  Guanin  into  Uric  Acid. — 
As  previously  stated  (Vol.  I  of  this  series,  p.  112,  Chem- 
istry of  the  Tissues),  the  physiological  relation  between  the 
two  bases  in  the  nucleinic  acid  molecule,  adenin  and  guanin, 
with  hypoxanthin,  xanthin  and  uric  acid  may  be  expressed 
by  the  following  schema : 

ADENIN   (C6H6N6)  GUANIN   (C6H6N60) 

N-C=NH  N-C=0 


'I  SI 

C-Nv  NH=C        C-Ns 

,     I       >C  \       I 

N-C-N'  N-C-N' 


HYPOXANTHIN    (C6H4N4O)  XANTHIN    (C5H4N4O2)  URIC   ACID    (C6H4N4O1) 

N-C=0  N-C=0  N-C=0 

/      \  /       I  /      I 

C       C    Nv         — ^      0=C         C-N.         — >      0=C        C-Nv. 

\    I      >c  \     1      >c  \    1      >c=o. 

n-c-n/  n-c-n/  n-c-n/ 

The  transformation  of  adenin  and  guanin  into  hypoxan- 
thin and  xanthin  by  replacement  of  their  NH  group  by  an 
atom  of  oxygen  is  ascribed  to ' '  deamidases ' '  whichmust  effect 
changes  of  the  type  indicated  in  the  formula :  R :  NH  + 
H20  =  R :  0  +  NH3.  Jones  recognizes  two  of  these 
enzymes,  " adenase"  and  " guanas e."  In  the  conversion 
of  hypoxanthin  into  xanthin  and  the  latter  into  uric  acid, 
oxidizing  ferments  known  as  " '  xanthoxydases "  are 
concerned. 

1  Literature  upon  the  Formation  of  Uric  Acid  from  the  Nucleins :  H. 
Wiener,  Ergebn.  d.  Physiol.,  1,  575-606,  1902;  F.  Samuely,  Handb.  d.  Biochem., 
1,  565-566,  1909;  A.  Ellinger,  ibid.,3',  575-576,  1910;  A.  Schittenhelm,  ibid., 
-V,  490-514,  519-531,  1910;  C.  Oppenbeimer,  Die  Fermente,  3d  ed.,  5,  166-170, 
370-372,  1910;    H.  M.  Vernon,  Ergebn.  d.  Physiol.,  9,  162-167,  1910. 


150  PHYSIOLOGY  OF  PURIN  METABOLISM 

A  great  deal  of  careful  work  has  been  devoted  to  the 
study  of  the  distribution  of  these  ferments  in  various  animal 
species,  in  experiments  with  tissue  pulp.2  Schittenhelm 3 
was  doubtless  correct  in  questioning  whether  all  the  differ- 
ential detail  involved  should  be  accepted  literally;  and 
whether,  if  one  of  these  ferments  were  missed  in  a  given  or- 
gan it  would  be  justifiable  to  infer  therefrom  that  it  is  also 
absent  from  the  living  organ.  In  some  aspects,  however, 
investigations  of  this  sort  may  be  productive  of  results. 

Guanin  Gout  in  the  Hog. — For  example,  it  was  found  that 
in  tissues  of  the  hog  "guanase"  occurs  only  in  small  amount 
and  that  addition  of  guanin  to  extracts  of  spleen  and  liver 
was  followed  by  but  insignificant  increase  in  the  quantity  of 
xanthin  produced  in  course  of  the  digestion ;  but  that  adenin 
is  freely  converted  into  hypoxanthin.  An  interesting  cor- 
relation may  be  recognized  in  the  fact  that  normally  in  the 
urine  of  hogs  the  purin  bases  are  more  prominent  than  uric 
acid,  and  that  there  is  a  disease,  guanin-gout  of  the  hog,  in 
which  uric  acid  apparently  disappears  completely  from  the 
urine,  and  at  the  same  time  (in  analogy  to  the  deposit  of  uric 
acid  in  the  tissues  in  human  gout)  guanin  is  deposited  in  the 
muscles,  cartilages,  and  in  the  liver.  The  lack  of  ' '  guanase ' ' 
apparently  interferes  here  with  the  normal  formation  of 
uric  acid,  which  in  the  hog  is  for  the  most  part  further  cata- 
bolized  into  allantoin.4 

Nucleases  and  Deamidases. — The  chemical  conversion  of 
the  purin  bases  must,  however,  be  preceded  by  their  cleavage 
from  the  molecule  of  nucleinic  acid,  which  takes  place  in  the 
nucleins  of  the  food  in  the  intestine  through  the  agency  of 

2  Cf.  especially  the  numerous  studies  of  A.  Schittenhelm,  as,  too,  of  W.  Jones 
(with  C.  L.  Partridge,  W.  C.  Winternitz,  C.  R.  Austrian,  Amberg  and  others). 

SA.  Schittenhelm,  Handb.  d.  Biochem.,  4',  509,  1910;  W.  Jones,  Zeitschr.  f. 
physiol.  Chem.,  45,  84,  1905. 

3  A.  Schittenhelm,  Handb.  d.  Biochem.,  4',  509,  1910;  W.  Jones,  Zeitschr.  f. 
W.  Jones  and  C.  R.  Austrian  (Johns  Hopkins  Univ.) ,  ibid.,  48,  HO,  1906;  L.  B. 
Mendel  and  J.  F.  Lyman  (Yale  Univ.),  Jour,  of  Biol.  Chem.,  8,  115,  1910;  A. 
Schittenhelm,  Zeitschr.  f.  physiol.  Chem.,  66,  53,  1910;  L.  B.  Mendel,  and  P.  H. 
Mitchell  (Yale  Univ.),  Amer.  Jour,  of  Physiol.,  22,  97,  1907. 


NUCLEASES  AND  DEAMIDASES  151 

"nucleases"  (cf.  Vol.  I  of  this  series,  p.  128,  Chemistry  of  the 
Tissues).  From  recent  experiments  of  London,  Schitten- 
helm  and  K.  Wiener,  in  which  a  series  of  dogs  (normal,  with- 
out stomach,  without  pancreatic  juice — ligation  of  the  excre- 
tory ducts  of  the  pancreas,  and  without  pancreas)  were  fed 
upon  nucleinic  acid,  it  was  determined  that  the  cleavage  of 
the  nucleinic  acid  is  to  be  entirely  ascribed  to  the  ferments 
of  the  intestinal  juice.  The  cleavage  always  stops  at  the 
stage  of  nucleosides,  which  undergo  no  further  dissociation 
in  the  intestine,  the  purins  remaining  in  combination  with  the 
sugar  of  the  nucleinic  acid  molecule  (as  do  also  the  pyri- 
midin  bases)  in  all  experiments.  In  the  lower  segments  of 
the  bowel  the  splitting  influence  of  bacteria  may  be  associated 
with  that  of  the  intestinal  ferments.5  The  resorption  of  the 
purin  bodies  takes  place  by  way  of  the  blood,  not  with  the 
lymph.6 

Cleavage  of  the  nucleinic  acids  in  the  animal  tissues  is 
undoubtedly  a  very  complicated  process.  Two  kinds  of 
nucleases  involved  are  differentiated:  "purinnucleases," 
which  split  off  the  purin  bases,  and  " phosphornucleases," 
which  separate  phosphoric  acid  from  the  molecule;  the 
nucleosides  (combinations  of  purin  bases  and  carbohy- 
drate), however,  remaining  intact.7  It  may  be  recalled  (cf. 
Vol.  I  of  this  series,  pp.  123-125,  Chemistry  of  the  Tissues) 
that  the  carbohydrate  group  in  the  nucleinic  acid  molecule  is 
intercalated  between  phosphoric  acid  and  the  base : 

Phosphoric  acid  < Carbohydrate >.  Base. 

Further  complication  of  the  situation  arises  from  the  fact 
that  deamidization  of  the  purin  bases  may  also  take  place  at 
this  stage,  provided  they  are  still  in  organic  combination,  in 

6E.  S.  London,  A.  Schittenhelm  and  K.  Wiener  (Erlangen  and  S't.  Peters- 
burg), Zeitschr.  f.  physiol.  Chem.,  77,  86,  1912. 

6  J.  Biberfeld  and  J.  S.  Schmid  (Breslau),  Zeitschr.  f.  physiol.  Chem.,  60, 
292,  1909. 

7  Amberg  and  W.  Jones  (Johns  Hopkins  Univ.),  Zeitschr.  f.  physiol.  Chem., 
73,  407,  1911. 


152  PHYSIOLOGY  OF  PURIN  METABOLISM 

such  manner  that,  according  to  Schittenhelm,8  deamidization 
may  involve  either  free  or  fixed  purin  bodies ;  and  for  that 
reason  it  is  essential  to  distinguish  between  purin- 
deamidases  and  nucleosiddeamidases. 

It  may  be  seen  that  in  the  catabolism  of  the  purin  bases 
included  in  the  nucleinic  acid  molecule  into  uric  acid  a  great 
many  different  possibilities  enter,  and  that  we  must  assume 
a  coordination  of  nucleases  and  nucleoside-splitting  fer- 
ments, of  purin-deamidases  and  nucleosiddeamidases,  as 
well  as  a  number  of  oxidases.  According  to  Levene  and 
Medigreceanu 9  the  nucleinic  acids  are  made  up  of  nucleo- 
tids,  a  type  of  which,  according  to  these  authors,  may  be  seen 
in  guanylic  acid  (Vol.  I  of  this  series,  pp.  125-128,  Chemistry 
of  the  Tissues),  to  which  they  ascribe  the  simple  constitution 
of  phosphoric  acid-pentose-guanin.  They  then  differentiate 
in  the  fermentation-cleavage  of  nucleinic  acids  between 
nucleinases,  which  split  up  the  nucleinic  acid  molecule  into 
nucleotids,  and  nucleotidases,  which  in  turn  catabolize  the 
nucleotids. 

What  an  enormous  amount  of  work  is  still  to  be  accom- 
plished before  we  can  be  in  position  to  clearly  define  the 
physiological  and  pathological  influence  of  any  one  of  these 
factors !  As  a  matter  of  fact  this  is  only  the  beginning  of 
the  difficulty. 

Nuclear  Destruction  and  Urinary  Purins. — The  next 
question  is  that  of  the  origin  of  the  endogenous  and  exog- 
enous urinary  purins,  about  which  it  is  safe  to  say  that 
veritable  rivers  of  ink  have  run  dry  in  advancing  to  a  point 
where  (and  this  is  always  a  good  sign)  the  matter  can  be 
properly  stated  in  a  few  words.  At  present  we  know  that 
the  exogenous  portion  of  the  urinary  purins  depends  in 
mammals  upon  the  quantity  of  free  or  combined  purins  in 
the  food,  bearing  in  mind  moreover  the  further  conversion  of 

8 A.  Schittenhelm  and  K.  Wiener  (Erlangen),  Zeitschr.  f.  physiol.  Chem., 
77,  77,  1912. 

9  P.  A.  Levene  and  F.  Medigreceanu  (Rockefeller  Instit.,  New  York),  Jouiv 
of  Biol.  Chem.,  9,  65,  375,  389,  1911. 


RELATION  TO  MUSCULAR  ACTIVITY  153 

uric  acid,  especially  the  formation  of  allantoin  which  is  so 
prominent  in  many  animals  (vide  infra). 

As  far  as  the  endogenous  fraction  is  concerned  it  is  known 
that  the  purin  bases  set  free  in  the  disintegration  of  cellular 
nuclei  in  all  tissues  eventually  appear  in  the  form  of  urinary 
purins.  There  is  reason  for  avoiding  a  restricted  concep- 
tion which  would  make  the  leucocytes,  the  muscles,  the 
digestive  glands  10  or  the  kidneys  alone  responsible  for  the 
endogenous  production  of  uric  acid ;  it  is  better  to  look  upon 
it  as  the  expression  of  a  continuous  and  general  cellular 
wear.  Precisely  because  this  process  of  wearing  out  and 
gradual  removal  of  cells  is  a  very  constant  and  regular  one, 
at  least  when  serious  pathological  changes  are  not  present, 
a  relative  constancy  in  the  endogenous  urinary  purin  frac- 
tion is  to  be  expected  for  each  individual,  as  first  observed 
by  R.  Burian  and  H.  Schur  and  afterwards  confirmed  by  a 
number  of  other  writers.11  Briefly  stated,  the  active  metab- 
olism of  the  growing  body,  the  experimental  exaggeration  of 
glandular  activity  by  pilocarpin,  the  increase  of  cell  de- 
struction by  use  of  Röntgen  rays,  and  very  many  pathologi- 
cal disturbances  like  phosphorus  poisoning,  hepatic  atrophic 
cirrhosis,  jaundice,  Eck's  fistula,  fever,  leukaemia,  etc.,  are  all 
capable  of  increasing  the  endogenous  fraction  of  urinary 
purins.12 

Relation  of  Purin  Metabolism  to  Muscular  Activity. — 
There  is  only  one  point  which  requires  any  further  dis- 
cussion in  this  connection,  namely,  that  of  the  relation  of  the 
purins  to  muscular  labor,13  a  matter  heretofore  dealt  with  in 

10  O.  Siven  (Helsingfors) ,  Pfliiger's  Arch.,  1^6,  449,  1912. 
n  Cf.  E.  W.  Rockwood,  Amer.  Jour,  of  Physiol.,  12,  38,  1904;    F.  Mares, 
vide  infra. 

12  B.  Hirschstein  (F.  Umber's  Clinic),  Arch.  f.  exper.  Path.,  57,  229,  1907; 
Th.  Brugsch  and  A.  Schittenhelm,  Zeitschr.  f.  exper.  Path.,  4,  761,  1907; 
O.  Siven  (Helsingfors),  Skan.  Arch.  f.  Physiol.,  18,  177,  1906;  S.  Bondi  and 
F.  König,  Wiener  med.  Wochenschr.,  1910,  Nos.  44-45 ;  F.  Mares,  F.  Smetanka 
(Physiol.  Institut.  Czech.  Univ.,  Prague),  Pflüger's  Arch.,  13'h  59,  1910;  138, 
217,  1911. 

13  R.  Burian,  Med.  Klinik,  1905,  No.  6,  and  1906,  Nos.  19-21. 


154  PHYSIOLOGY  OF  PURIN  METABOLISM 

considering  the  chemistry  of  muscular  tissue  (v.  Vol.  I  of 
this  series,  p.  159,  Chemistry  of  the  Tissues).  It  cannot  be 
doubted  that  muscular  activity  has  a  part  in  the  formation  of 
the  endogenous  urinary  purins.  The  fact,  however,  that 
Schittenhelm 14  has  found  no  striking  reduction  of  the 
endogenous  amount  in  human  beings  with  well  marked  mus- 
cular ati  ophy  would,  however,  contradict  the  idea  that  the 
bulk  of  these  substances  originates  in  muscle  tissue.  Siven, 
too,  failed  to  recognize  any  characteristic  influence  of  free 
muscular  movements  upon  the  endogenous  purin  metabolism 
in  man  15 ;  while  Goudberg  invariably  found  the  uric  acid 
increased  in  starving  rabbits  after  muscular  spasms  pro- 
duced by  faradism.16  Finally  it  should  be  noted  that  mus- 
cular involvement  in  processes  concerned  with  heat  regula- 
tion is  apparently  more  likely  to  influence  the  purin 
excretion  than  voluntary  contractions.  The  increased  uric 
acid  excretion  of  fever  and  its  nocturnal  diminution  are 
perhaps  related  to  the  same  type  of  processes.17 

Synthetic  Formation  of  Uric  Acid  in  Birds  and  Reptiles. 
— Being  in  some  measure  satisfied  of  the  production  of  uric 
acid  through  processes  of  oxidation  from  nucleins,  attention 
should  be  directed  to  the  synthetic  production  of  uric  acid.18 
It  is  known  that  the  major  portion  of  the  nitrogen,  which  in 
mammals,  amphibians  and  fish  is  excreted  as  urea,  is  repre- 
sented in  birds,  reptiles  and  also  in  many  invertebrates  19  by 
uric  acid,  which  is  produced  in  them  synthetically.  What  is 
known  of  the  mechanism  of  this  process? 

14  A.  Schittenhelm,  Handb.  d.  Biochem.,  4'  521,  1910. 

15  V.  O.  Siven,  1.  c. 

18  A.  Goudberg  (Hamburg),  Zeitschr.  f.  Neurol,  u.  Psych.,  8,  487,  1912. 
"  E.  P.  Cathcart,  J.  B.  Leathes,  E.  L.  Kennaway,  cited  by  A.  Ellinger, 
Handb.  d.  Biochem.,  4',  576,  1910. 

18  Literature  upon  the  Synthesis  of  Uric  Acid :  H.  Wiener,  Ergebn.  d. 
Physiol.,  1,  606-615,  1902;  A.  Magnus-Levy,  v.  Noorden's  Handb.,  1,  126-129, 
1906;  A.  Schittenhelm,  Handb.  d.  Biochem.,  \ ,  522-525,  1910. 

19  Cf.  O.  v.  Fürth,  Vergl.  chem.  Physiol,  d.  niederen  Tiere,  pp.  258-303, 
Jena,  1903. 


LACTIC  ACID  IN  URIC  ACID  SYNTHESIS  155 

The  skeletal  plan  of  the  uric  acid  molecule  may  be  repre- 
sented as  consisting  of  two  fractions  of  urea  fixed  to  a  chain 
of  three  atoms  of  carbon : 

/NH2  I  NH2  NH— CO 

CO  C  \(X)    — ►    CO  C— NHX 

\Nn     |NH/  \  II  >CO 

NH*  \Q  NH*  NH— C— NH/ 

Our  ideas  in  reference  to  the  urea  rests  required  in  the 
synthesis  of  uric  acid  are  fairly  clear.  According  to  the 
investigations  of  Knieriem,  Jaff e  and  Hans  H.  Meyer,  as  well 
as  those  of  Schröder,  there  can  be  no  question  as  to  the  abil- 
ity of  the  liver  in  birds  to  construct  uric  acid  from  ammonia 
salts,  aminoacids,  as  well  as  from  urea.  The  hypothesis  that 
in  the  avian  body,  just  as  in  mammals,  the  protein  nitrogen  is 
first  broken  down  into  urea,  and  subsequently  as  a  secondary 
process  is  synthesized  into  a  complex  of  two  urea  rests  and 
a  group  of  three  carbon  atoms  is  an  entirely  satisfying 
one. 

What  is  the  significance  of  this  triple  group  of  carbon 
atoms?  Minkowski's  well-known  experiment,  in  which  he 
noted  the  appearance  of  lactic  acid  and  ammonia  in  the  urine 
of  geese  from  which  the  liver  had  been  extirpated,  has  forced 
lactic  acid  for  the  past  nearly  twenty  years  prominently  into 
consideration,  and  has  apparently  harmonized  the  general 
subject.  It  has  been  proved  that  the  appearance  of  lactic  acid 
is  due  to  the  loss  of  the  hepatic  function ;  as  ligation  of  all  of 
the  hepatic  vessels  produces  the  same  effect,  but  if  even  a 
single  branch  of  the  hepatic  artery  be  open  there  is  no  forma- 
tion of  lactic  acid.  To  prove  that  the  failure  of  uric  acid  for- 
mation is  actually  due  to  the  exclusion  of  the  liver  and  is  not 
in  some  way  a  secondary  result  of  accumulation  of  lactic  acid 
in  the  body,  requiring  considerable  ammonia  for  neutraliza- 
tion and  thus  interfering  with  synthesis  of  uric  acid,  we  may 
recall  the  fact  that  (as  Sigmund  Lang  was  able  to  show  in 
Hofmeister 's  laboratory)  introduction  of  alkali  into  geese 
with  excluded  livers  is  not  followed  by  any  increase  in  the 


156  PHYSIOLOGY  OF  PURIN  METABOLISM 

disturbed  uric  acid  synthesis.  H.  Wiener  has  noted  in  de- 
hepatized  birds  that  if  the  economy  is  experimentally  flooded 
with  urea,  lactic  acid  and  especially,  too,  a  number  of  di- 
basic acids  in  whose  structure  there  occurs  a  chain  of  three 
carbon  atoms,  as  malonic  acid  (COOH.CH2.COOH),  tar- 
tronic  acid  (COOH  -  CH(OH)  -  COOH)  and  mesoxalic  acid 
(COOH- CO -COOH)  are  capable  of  giving  rise  to  an 
increase  in  the  uric  acid  elimination.  The  synthesis  of  uric 
acid  in  such  case  may  proceed  somewhat  as  follows : 

LACTIC   ACID      TARTRONIC   ACID        DIALURIC   ACID  URIC   ACID 

CH3  COOH  NH— CO  NH— CO 

I  I  /I  /I 

CH.OH — ^CH.OH — >     CO  CH(OH)    — >  CO  C— NH 

+  urea       \         |    +   urea  \  ||  \ro 

COOH  COOH  NH— CO  NH-C-NH/^U' 

The  recent  recognition  of  a  synthesis  of  uric  acid  from 
dialuric  acid  and  urea  20  may  be  regarded  as  the  capstone  of 
the  construction. 

An  important  recent  investigation  by  Ernst  Friedmann 
and  H.  Mandel 21  would  indicate  that  we  are  still  far 
from  the  truth.  Contrary  to  Kowalewski  and  Salaskin,  who 
found  an  increase  in  the  amount  of  uric  acid  in  the  blood 
used  in  perfusion  of  the  excised  goose-liver  after  lactate  of 
ammonia  was  added,  the  above  named  authors  were  un- 
able to  in  any  way  influence  uric  acid  formation  by  introduc- 
ing either  lactate  of  sodium  and  urea,  or  malonate  of  sodium 
and  urea.  On  the  contrary  a  remarkably  large  formation  of 
uric  acid  was  a  striking  feature  when  perfusion  was  per- 
formed with  normal  blood  unchanged  by  any  additions, 
clearly  not  dependent  upon  washing  out  of  previously 
formed  uric  acid  but  indicative  rather  of  an  actual  new 
formation.  This  brings  up  the  question  whether  perhaps 
the  synthesis  of  uric  acid  is  not  accomplished  in  a  very  dif- 
ferent manner  than  indicated  in  the  above  schema.     It  is 

20  G.  Izar  (Ascoli's  Lab.,  Catania),  Zeitschr.  f.  pbysiol.  Chem.,  13,  317,  1911. 

21  E.  Friedmann  and  H.  Mandel  (First  Med.  Clinic,  Berlin),  Arch.  f.  exper. 
Pathol.  (Schmiedeberg  Festschrift),  p.  199,  1908. 


SYNTHETIC  PURIN  FORMATION  IN  MAMMALS    157 

very  evident  that  the  problem  cannot  be  regarded  at  present 
as  solved. 

It  has  been  actually  shown  in  Minkowski's  laboratory 
that,  as  previously  suspected,  besides  the  synthetic  formation 
in  the  avian  body  there  is  also  an  oxidation  formation  of 
uric  acid  in  small  amounts  in  complete  analogy  to  the  process 
in  mammals. 

Synthetic  Purin  Formation  in  Mammals. — There  is  no 
evidence  at  all  at  present  to  indicate  that  uric  acid  is 
synthetically  produced  in  mammalian  animals  and  man 
along  with  its  oxidative  production,  in  analogy  to  the  proc- 
ess seen  in  birds,  as  was  asserted  by  H.  Wiener.22  However, 
there  is  no  doubt  as  to  the  ability  even  of  the  mam- 
malian body  to  construct  purin  complexes  in  prepara- 
tion for  their  incorporation  in  the  molecules  of  nucleinic 
acid.  The  most  important  points  in  this  connection  have 
been  previously  considered  (Vol.  I  of  this  series,  p.  129, 
Chemistry  of  the  Tissues).  Proof  is  available  not  only  in 
case  of  the  eggs  of  the  silk  moth  and  of  the  hen,  the  salmon 
in  starvation,  but  also  in  case  of  growing  sucklings  and  of 
rats  fed  upon  purin-f ree  diet,  that  the  animal  body  is  able  to 
construct  de  novo  the  bases  necessary  for  purin  formation 
out  of  practically  any  components  of  the  protein  molecule ; 
and  that  it  is  not  restricted  exclusively  to  purin  bases  of 
exogenous  origin.22a  But  no  one  knows  just  how  this  con- 
struction takes  place.  It  has  not  been  successfully  shown  by 
feeding  experiments  that  transformation  takes  place  of  de- 

N— C 

rivatives  of  the  pyrimidin  nucleus,23  C       C,  (Vol.  I  of  this 

N— C 


22  P.  Burian,  Zeitschr.  f.  physiol.  Chem.,  J@,  497,  1905;  W.  Pfeiffer  (F.  Hof- 
meister's  Lab.,  S'trassburg,  and  Quincke's  Clinic,  Kiel),  Hofmeisters  Beitr.,  10, 
324,  1907. 

22a  E.  V.  McCollum  (Wisconsin),  Amer.  Jour,  of  Physiol.,  25,  120,  1909; 
L.  S.  Fridericia  (Copenhagen),  Skandin.  Arch.  f.  Physiol.,  26,  1,  1912;  cf.  therein 
Literature. 

23  L.  B.  Mendel  and  V.  C.  Myers  (Yale  Univ.),  Amer.  Jour,  of  Physiol.,  26, 
77,  1910. 


158  PHYSIOLOGY  OF  PURIN  METABOLISM 

series,  p.  113,  Chemistry  of  the  Tissues)  or  of  a  derivative 

Q n 

of  the  imidazol  nucleus,    |        >C  ,  histidin  ,24  into  the  purin 

C— n/ 
N— C 

nucleus,    C        C— Nv       in  which  both  the  former  nuclei  are, 

\      I       V 

N— C— N' 

so  to  say,  included. 

Allantom  as  an  End-product  of  Mammalian  Purin  Me- 
tabolism.— We  come  now  to  the  most  abstruse  and  debated 
portion  of  the  uric  acid  problem,  that  of  uric  acid  destruction 
in  the  body,  uricolysis.  For  the  past  decade,  in  spite  of  all  the 
study  devoted  to  it,  this  problem  has  remained  fixed,  un- 
doubtedly for  the  reason,  at  present  easily  appreciable,  that 
the  dominating  position  which  is  occupied  by  allantoin  in  the 
nuclein  metabolism  in  mammals  was  entirely  overlooked. 
The  ignorance  which  previously  prevailed  upon  the  general 
subject  first  began  to  lessen  when  Wilhelm  Wiechowski  con- 
tributed to  metabolic  investigation  an  exact  method  of  de- 
termining allantoin  and  took  up  in  definitive  manner  the 
problem  of  uric  acid  destruction  in  a  series  of  very  carefully 
conducted  studies.25 

After  it  became  known  from  repeated  investigations  28 
that  living  excised  tissues  of  mammals  are  capable  of  de- 
stroying uric  acid,  Wiechowski  proved  that  it  is  completely 
oxidized  in  the  process  into  allantoin  without  undergoing 
further  change  : 

URIC  ACID  ALLANTOIN 

NH— CO  NH2 

CO  C— NHV  — >  CO  CO— NHX 

\      II        >co  \       I  >co. 

NH-C-NH/  HN-CH-NH/ 

34  E.  Abderhalden,  H.  Einbeck  and  J.  Schmid,  Zeitschr.  f.  physiol.  Chem., 
68,  395,  1911. 

25 W.  Wiechowski  (J.  Pohl's  Lab.,  Prague),  Hofmeister's  Beitr.,  9,  247, 
295,  1907;  11,  109,  1907;  Arch.  f.  exper.  Pathol.,  60,  185,  1909;  Biochem. 
Zeitschr.,  25,  431,  1910;    cf.  in  this  last  the  Literature  upon  Uricolysis. 

26  Stokvis,  Chassevant  and  Riebet,  Ascoli,  Jacoby,  Schittenhelm,  Burian, 
Austin,  Almagia,  Wiener.     Cf.  H.  M.  Vernon,  Ergebn.  d.  Physiol.,  9,  168,  1910. 


ALLANTOIN  AS  AN  END-PRODUCT  159 

That  this  is  really  the  expression  of  a  physiological 
process  is  evidenced  directly  by  the  fact  that  in  the  mammals 
carefully  studied  from  this  point  of  view  (dog,  cat,  rabbit, 
hog,  cow)  excretion  of  uric  acid  and  of  the  purin  bases  is 
decidedly  overshadowed  by  allantoin,  as  shown  from  obser- 
vations of  Schittenhelm,  Abderhalden,  Underhill,  L.  B.  Men- 
del and  others.  Parenterally  introduced  uric  acid  is  com- 
pletely excreted  by  dogs  and  rabbits,  in  by  far  the  greater 
proportion  as  allantoin,  and  only  in  minor  amount  as  uric 
acid.  Nucleinic  acid  from  thymus  derivation,  too,  when  in- 
troduced with  the  food,  according  to  Schittenhelm 27  under- 
goes cleavage  in  the  body  of  the  dog  in  a  way  that  the  great 
bulk  (93-97  per  cent.)  of  its  purins  appear  as  allantoin,  and 
only  the  small  residual  percentage  is  partitioned  as  uric  acid 
and  purin  bases.  The  author's  pupil,  W.  Hirokawa,28  ob- 
tained similar  figures  when  nucleinic  acid  was  fed  to  dogs ; 
although  the  purins  did  not  appear  in  the  urine  entirely  free 
from  residue.  Likewise,  too,  in  the  pig29  after  adminis- 
tration of  nucleinic  acid  the  purins  for  the  most  part  appear 
in  the  allantoin  fraction.  On  the  basis  of  these  observations, 
supplemented  by  numerous  older  findings  bearing  upon  the 
conversion  of  uric  acid  and  nucleinic  substances  into  allan- 
toin,30 Wiechowski  has  been  thoroughly  corroborated  in 
his  statement  that  allantoin  is  to  be  regarded  and  accepted 
as  an  end-product  of  uric  acid  metabolism,  and  that  besides 
allantoin  no  other  products  (neither  oxalic  acid,  glycocoll  nor 
urea)  of  the  intermediate  uric  acid  metabolism  are  met  in 
mammalian  animals. 

Further  explanation  is  not  necessary  for  appreciation  of 
the  fact  that  allantoin,  an  end-product  of  the  normal  vital 
catabolism  of  nucleoproteids  and  nucleinic  acids,  appears  in 
the  catabolism  of  the  same  substances  in  case  of  intoxication 

37  A.  Schittenhelm,  Zeitschr.  f.  physiol.  Chem.,  62,  80,  1909. 
28  W.   Hirokawa,   Biochem.   Zeitschr.,   26,   441,    1910;     under   direction   of 
O.  v.  Fürth. 

»A.  Schittenhelm,  Zeitschr.    f.  physiol.  Chem.,  66,  53,  1910. 
80  Salkowski,  Minkowski,  Th.  Cohn,  L.  B.  Mendel  and  others. 


160  PHYSIOLOGY  OF  PURIN  METABOLISM 

with  protoplasmic  poisons  (hydrazin,  hydroxylamine  and 
semicarbazide)  as  well  as  in  autolysis,  as  repeatedly  observed 
by  Borissow  and  by  J.  Pohl  and  his  collaborators.31 

In  what  organs  the  change  from  uric  acid  into  allantoin 
takes  place  is  not  known ;  that  it  is  not  limited  to  the  liver  is 
proved  by  observations  on  dogs  with  Eck's  fistulas.32 

While  parenterally  introduced  nucleinic  acid  is  appar- 
ently changed  practically  completely  into  allantoin  by  the 
mammalian  body,  this  is  not  by  any  means  always  the  case 
with  the  nucleinic  acid  introduced  by  the  mouth.  In  rabbits 
only  half  or  less  of  the  nitrogen  of  the  bases  appears  as 
allantoin  in  the  urine  under  such  circumstances.  According 
to  Wiechowski  this  may  be  easily  explained  by  the  fact  that 
in  the  alkaline  intestinal  contents  extensive  destruction  of 
allantoin  takes  place,  apparently  without  necessity  for  inter- 
vention of  bacteria,  but  certainly  with  such  aid.  On  the 
other  side  of  the  intestinal  wall,  however,  the  allantoin  is  a 
stable  product. 

Fate  of  the  Intermediary  Uric  Acid  in  Man. — As  far  as 
uricolysis  in  the  lower  animals  is  concerned  there  is  a  fair 
unanimity  of  opinion;  the  more  divergent,  however,  the 
opinions  as  to  the  destruction  of  uric  acid  in  human 
metabolism. 

For  a  decade  the  physiology  and  pathology  of  purin 
metabolism  remained  unchanged  under  the  domination  of 
the  hypothesis  that  a  marked  destruction  of  uric  acid  takes 
place  in  the  human  body.  In  conditions  in  which  (as  in  gout) 
special  accumulation  of  uric  acid  was  assumed  to  exist,  the 
fault  was  always  referred  to  some  lowering  of  the  power  of 
the  tissues  to  destroy  uric  acid.  In  the  course  of  the  last 
few  years  these  ideas  have  undergone  appreciable  change. 

Absence  of  Uricase  in  Human  Tissues. — As  has  been 
said,  uric  acid  destruction,  with  formation  of  allantoin, 

"Literature:     W.  Wiechowski,  Hofmeister's  Beitr.,  9,  306,  1907. 
82  E.  Abderhalden,  E.  S.  London  and  A.  Schittenhelm,  Zeitschr.  f.  physiol. 
Chem.,  61,  413,  1909. 


ABSENCE  OF  URICASE  IN  HUMAN  TISSUE         161 

takes  place  with  great  intensity  in  the  pulp  of  mam- 
malian tissues.  (It  takes  place  apparently  in  other  verte- 
brates as  well ;  it  is  said  that  the  liver  of  the  ray  is  from 
this  standpoint  more  capable  than  any  other  vertebrate 
tissue.)  33  There  have  been  a  number  of  attempts  to  isolate 
an  actual  ferment,  "uricase"  (as  far  as  it  is  possible  to 
speak  of  isolation  in  case  of  enzymes).34  Wiechowski  here 
made  the  important  discovery  that  living  excised  human  tis- 
sues are  unable  to  break  down  uric  acid  under  conditions  in 
which  the  tissues  of  lower  mammals  prove  efficient,  and  that 
the  former  therefore  must  be  regarded  as  not  conforming  to 
the  usual  rule.  This  has  been  confirmed  from  so  many 
sources  35  that  there  can  be  no  doubt  as  to  its  correctness.36 
The  objection  raised  that  invariably  a  preuricase  is  present 
but  is  prevented  from  manifesting  itself  because  of  the  an- 
tagonism of  inhibiting  substances  can  scarcely  be  accepted, 
if  for  no  other  reason  than  that  other  ferments  which  are 
active  against  purins,  as  xanthinoxydase  and  guanase,  are 
found  without  any  difficulty  in  the  human  tissues.  "If," 
says  Wiechowski,37  "äs  is  amply  confirmed  by  all  observers, 
human  tissues  build  up  uric  acid  with  ease  from  guanin  and 
xanthin  but  do  not  catabolize  the  substance  thus  formed,  in 
contrast  to  animal  tissues,  which  oxidize  the  uric  acid 
further  into  allantoin,  it  seems  to  me  the  assembling  of  these 

33  V.  Scaffidi  (Zool.  Station,  Naples),  Biochem.  Zeitschr.,  18,  506,  1909; 
25,  296,  411,  415,  1910. 

81  W.  Wiechowski  and  W.  Wiener  (J.  Pohl's  Lab.,  Prague),  Hofmeister's 
Beitr.,  9,  247,  1907;  F.  Battelli  and  L.  Stern  (Geneva),  Biochem.  Zeitschr.,  19, 
219,  1909;  G.  Galeotti  (Naples),  ibid.,  30,  374,  1911. 

35  Battelli  and  Stern,  Miller  and  Jones,  J.  G.  Wells  and  H.  J.  Corper,  cited 
by  Wiechowski,  Biochem.  Zeitschr.,  25,  434,  1910. 

30  It  would  probably  be  going  too  far  to  deny  entirely  all  possibility  of  a 
uricolysis  in  human  tissues,  as  there  have  been  positive  findings  also  in  this 
direction,  as  those  of  W.  Pfeiffer,  Croftan  and  Schittenhelm.  Consult  in  refer- 
ence to  the  physiological  importance  of  the  subject:  W.  Wiechowski,  Arch.  f. 
exper.  Pathol.,  60,  199-200,  1907.  "  I  believe  that  I  am  in  position  to  conclude 
with  a  fair  certainty,"  says  Wiechowski,  "  that  in  carefully  prepared  experi- 
ment-conditions in  which  living  excised  animal  tissues  oxidize  uric  acid  vigor- 
ously, human  tissues  are  practically  inactive." 

27  W.  Wiechowski,  Biochem.  Zeitschr.,  25,  436,  1900. 

11 


162  PHYSIOLOGY  OF  PURIN  METABOLISM 

findings  constitutes  a  valuable  scientific  contribution  to  our 
knowledge  of  the  fate  of  uric  acid  in  human  beings. ' ' 

Fate  of  Experimentally  Introduced  Purins  in  Human 
Metabolism. — Another  point  of  considerable  importance  is 
the  fate  of  artificially  introduced  uric  acid  in  the  human 
metabolism.  After  feeding  nucleinic  acid  to  human  be- 
ings Schittenhelm,  Brugsch  and  Frank  have  recovered  as 
a  rule  the  greater  part  of  the  purin  base  nitrogen  in  the  urea 
fraction,  a  smaller  portion  in  the  uric  acid  fraction  and  only  a 
very  small  proportion  as  nitrogen  of  the  purin  bases.38  Al- 
lantoin  which  predominates  in  metabolism  in  animals  is  of 
little  importance  here,  and  is  found  only  in  very  small 
amounts  in  the  human  urine.  However,  according  to  Wie- 
chowski's  results,  uric  acid  introduced  subcutaneously  is 
recovered  for  much  the  most  part  as  such  (up  to  90  per  cent.) 
in  the  urine. 

There  is  a  difference  of  opinion  as  to  the  importance  of 
this  last  result,  between  Wiechowski  on  the  one  hand,  and 
Brugsch  and  Schittenhelm  on  the  other.  Schittenhelm  be- 
lieves that  because  of  its  toxicity  subcutaneous  injections  of 
uric  acid  are  not  suited  for  conclusions  with  reference  to 
normal  metabolic  processes,  and  thinks  it  C3rtain  that  uric 
acid  is  in  some  proportion  further  catabolized  in  human  me- 
tabolism, with  production  of  urea.39  This  view  agrees  with 
that  of  Burian,  who  assumes  that  of  the  uric  acid  which 
enters  the  circulation  from  without  or  which  is  produced  in 
the  body  by  the  breaking  down  of  the  nucleins,  in  man  al- 
ways about  half  is  destroyed  and  only  the  other  half  is 
excreted  unchanged;  for  which  reason  he  multiplies  the 
amount  of  excreted  uric  acid  by  the  "integrative  factor  2" 
in  order  to  obtain  the  total  uric  acid  which  entered  the  cir- 
culation in  the  course  of  a  day  upon  purin-free  diet.40 

M  R.  H.  Plimmer,  M.  Dick  and  C.  C.  Lieb,  Jour,  of  Physiol.,  89,  98,  1909. 

»A.  Schittenhelm,  Handb.  d.  Biochem.,  4',  516,  1910;  cf.  also  L.  B.  Mendel 
and  J.  F.  Lyman  (Yale  Univ.),  Jour,  of  Biol.  Chem.,  8,  115,  1910. 

40  R.  Burian,  Med.  Klinik,  1905,  No.  6,  and  1906,  Nos.  19-21.  Consult  in 
these  and  in  the  contributions  of  R.  Burian  and  H.  Schur  the  Literature. 


PURINS  IN  HUMAN  METABOLISM  163 

To  this  Wiechowski  makes  adverse  reply.  He  acknowl- 
edges that  the  subcutaneous  injection  of  uric  acid  severely 
taxes  the  metabolism.  It  is  not  impossible  that  a  toxic  ac- 
tion, which  must  be  taken  into  consideration,  but  permitted 
to  proceed,  may  afford  correct  conclusions  in  animal  ex- 
perimentation ;  in  no  case,  however,  can  the  metabolic  dis- 
turbance produced  explain  why  the  greater  part  of  uric  acid 
which  has  been  parenterally  introduced  into  a  human  being 
is  excreted  unaltered. 

Schittenhelm 's  41  finding,  that  experimentally  introduced 
allantoin  is  not  affected  in  human  metabolism,  is  an  impor- 
tant one.  Were  uric  acid  catabolized  in  man,  as  in  animals, 
in  important  degree  into  allantoin,  we  might  expect  that  the 
latter  would  appear  in  the  urine;  but  actually  very  small 
amounts  only  of  this  substance  occur  normally  therein.42 

In  harmony  with  earlier  opinions  of  Otto  Löwi 43  and  of 
Soetbeer  and  Ibrahim,44  Wiechowski  concludes  that  inter- 
mediate uric  acid  is  not  broken  down  in  man  in  any  really  im- 
portant amount.  "For  this  conclusion  the  individual  con- 
stancy of  endogenous  uric  acid  excretion  is  a  favorable  point. 
For  how  else  can  this  be  explained  if,  as  shown,  the  reality  of 
a  so-called  integrative  factor  of  the  amount  decomposed  is 
not  to  be  assumed.  And  the  established  difference  between 
the  urine  of  mammals  and  of  man  on  purin-free  diet  (in  one 
case  a  rich  and  individually  constant  daily  allantoin  elimina- 
tion with  very  low  uric  acid  elimination  in  the  other  a  rich 
and  individually  constant  excretion  of  uric  acid  in  the 
twenty-four  hours  with  mere  traces  of  allantoin  excretion) 
may  be  looked  upon  as  entirely  satisfactory  and  logical  evi- 
dence of  the  inferred  position  of  the  human  being  in  relation 
to  uric  acid." 45    Finally  Wiechowski 45a  comes  to  the  point 

41  A.  Schittenhelm  and  K.  Wiener,  Zeitschr.  f.  physiol.  Chem.,  63,  283,  1909. 

42  K.  Ascher  (Prague),  Biochem.  Zeitschr.,  26,  370,  1910. 
48  O.  Löwi,  Arch.  f.  exper.  Pathol.,  /,//,  22,  1900. 

**  F.  Soetbeer  and  J.  Ibrahim  (Heidelberg),  Zeitschr.  f.  physiol.  Chem., 
35,  1,  1902. 

46  W.  Wiechowski,  Arch,  f .  exper.  Pathol.,  60,  206,  1904. 
46a  W.  Wiechowski,  .Biochem.  Zeitsch.,  25,  445,  1910. 


164  PHYSIOLOGY  OF  PURIN  METABOLISM 

that  all  the  objections  raised  by  Schittenhelm  and  others  are 
unsound.  ' '  I  am  compelled  to  remain  of  the  same  opinion  as 
before,  believing  it  to  be  well  founded  and  not  contradicted ; 
that  is,  that  the  changes  in  intermediate  uric  acid  proceed  in 
man  qualitatively  precisely  as  in  the  other  mammals,  that  is, 
that  it  is  transformed  by  oxidation  into  allantoin ;  but  quan- 
titatively they  lag  behind  so  much  that  uric  acid  must  be 
regarded  as  the  principal  product  of  purin  metabolism  in 
man." 

Wiechowski  's  view  has  very  recently  received  important 
support  from  the  results  of  a  personal  experiment  conducted 
by  Lewinthal  in  Friedrich  v.  Müller 's  Clinic  in  Munich,46  in 
which  the  investigator  injected  into  himself  xanthin  (dis- 
solved in  piperidin)  and  recovered  the  bulk  (89  per  cent.)  in 
the  urine  mainly  as  uric  acid.  Siven,  in  Helsingfors,47  like- 
wise concludes  from  experiments  upon  himself  that  the 
human  body  is  devoid  of  uricolytic  ability  and  that  purins 
when  they  have  once  gained  access  to  the  circulation  are  to 
be  looked  upon  as  end-products  of  metabolism. 

In  connection  with  the  exceptional  position  of  man  as  to 
purin  metabolism  it  is  instructive  to  note  that  the  uricolytic 
power  of  the  tissues  of  the  macacus  rhesus  species  of 
monkey  is  more  like  that  of  the  tissues  of  other  animals  than 
of  human  beings.48  According  to  "Wiechowski,  in  the  lower 
monkeys,  as  in  other  mammals,  allantoin  is  the  principal  end- 
product  of  purin  metabolism.  The  urine  of  the  chimpanzee, 
however,  corresponds  in  this  particular  with  human  urine.49 

Decomposition  of  Purins  in  the  Intestine. — The  fact 
that  dietary  purins,  whether  free  or  combined,  fail  to 
appear  either  as  uric  acid  or  allantoin  in  the  urine  can- 

40  W.  Lewinthal  (F.  v.  Müllers  Clinic,  Munich),  Zeitschr.  f.  physiol.  Chem., 
77,  273-274,  1912. 

47  V.  O.  Siven  (Helsingfors),  Pflüger's  Arch.,  1^5,  283,  1912. 

48  H.  G.  Wells  (Chicago),  Jour,  of  Biol.  Chem.,  7,  171,  1909-10. 
48  W.  Wiechowski,  Prager  med.  Wochenschr.,  1912,  275. 


DECOMPOSITION  OF  PURINS  IN  INTESTINE       165 

not  be  harmonized  with  the  assumption  that  these  sub- 
stances are  to  be  regarded  as  end-products  of  intermediary 
metabolism,  except  by  acknowledging  the  possibility  of  an 
important  degree  of  purin  destruction  in  the  bowel.50 
As  a  matter  of  fact,  we  have  no  ground  for  doubting  such 
a  possibility.  It  has  been  shown  that  uric  acid  undergoes  a 
spontaneous  dissociation  even  at  the  low  alkalinity  of  sodium 
bicarbonate  when  in  a  warm  temperature,51  and  is  even 
more  readily  catabolized  in  alkali  solution  when  acted  upon 
by  an  oxidizing  agent  :52 

URIC  ACID  TETRACARBONIMIDE         CARBONYLDIUREA  UREA 

NH-CO  NH-CO-NH  NH2         NH2  NH, 

CO  C-NH  CO  CO  CO  CO  CO 

\        ||        >CO   — >    I  I       — »■    I  I      — >    i 

NH-C-NH  NH-CO-NH  NH-CO-NH  NH,. 

The  oxidation  takes  place  in  a  strongly  ammoniacal  solution 
with  separation  of  imino-allantoin,53 


NH-CH-NH.CO.NH, 
NH- 


CO  < 

[-C=NH. 


It  is  doubtful,  it  is  true,  whether  such  oxidation-cleavage 
processes  play  any  part  in  the  usually  strongly  active  reduc- 
ing intestinal  contents.  However,  bacterial  cleavage  proc- 
esses must  not  be  overlooked,  an  example  of  which  may  be 
seen  in  the  action  of  the  uric  acid  bacillus  isolated  from 
chicken  excrement,  producing  a  fermentation  of  uric  acid 
into  urea  and  carbonic  acid  as  end-products.54 

Reconstruction  of  Uric  Acid. — It  is  difficult  to  realize  the 

50  P.  A.  Levene  and  F.  Medigreceanu  (Rockefeller  Instit.,  New  York),  Amer. 
Jour,  of  Physiol.,  27,  438,  1911. 

51  W.  Wiechowski,  Arch.  f.  exper.  Pathol.,  60,  200,  1907. 

"A.  S'chittenhelra  and  K.  Wiener,  Zeitschr.  f.  physiol.  Chem.,  62,  100,  1909; 
cf.  also  R.  Behrend,  Ann.  d.  Chem.,  333,  141,  1904;  365,  21,  1909. 

M  G.  Denicke,  Ann.  d.  Chem.,  3Jt9,  269,  1906. 

"  C.  Ulpiani  and  M.  Cingolini,  Gazzetta  Chimica  Ital.,  1908,  34,  377,  1904; 
cit.  in  Centralbl.  f.  Physiol.,  19,  166,  1904. 


166  PHYSIOLOGY  OF  PURIN  METABOLISM 

statements  of  Ascoli  and  Izar  55  to  the  effect  that  uric  acid 
may  reform  after  it  has  undergone  a  previous  decomposi- 
tion. These  authors  observed  the  disappearance  of  sodium 
urate  which  had  been  added  to  hepatic  pulp  in  the  incubator 
when  a  stream  of  air  was  conducted  through  it.  When  the 
material  was  left  in  the  incubator  with  air  excluded  it  is 
said  reformation  of  the  uric  acid  took  place.  Control  ex- 
periments are  said  to  have  shown  that  the  newly  formed  uric 
acid  did  not  come  from  any  cleavage  of  nucleins  belonging 
in  the  liver  pulp,  but  from  a  real  regeneration  of  the  decom- 
posed uric  acid.  From  what  has  been  said  (vide  supra)  it 
would  be  necessary  to  assume  that  in  oxidation-destruction 
of  uric  acid  in  liver  extracts  allantoin  would  be  formed.  That 
this  is  the  case  has  meanwhile  recently  been  shown  by 
Fasiani,  although  he  was  unable  to  confirm  the  regeneration 
of  the  uric  acid.56  The  author  prefers  to  postpone  any 
definite  opinion  upon  the  matter  until  the  conclusion  of 
experiments  now  in  course  in  his  laboratory. 

Methylated  Pur  in  Derivativ  es. — Besides  the  typical  purin 
bases  there  is  a  series  of  methylated  purin  derivatives  pres- 
ent in  small  quantities  in  urine,  which  originate  from  the 
caff  ein,  theobromin  and  theophyllin  of  coffee  and  tea.  Their 
nature  has  been  fully  demonstrated,  in  the  first  place  by 
their  synthetic  production  by  Emil  Fischer  and,  too,  espe- 
cially by  the  studies  of  Kost,  Albanese,  Bondzynski  and 
Gottlieb,  Salomon,  Krüger,  J.  Schmid  and  Schittenhelm.57 
The  schema  below  printed  may  serve  to  indicate  their  rela- 
tion (in  which,  as  in  previous  instances  the  writer  has 
omitted  for  brevity  hydrogen  atoms  and  double  bindings) : 

»M.  Ascoli  and  G.  Izar,  Zeitschr.  f.  physiol.  Chem.,  58,  529,  1909;  G.  Izar, 
ibid.,  65,  88,  1910. 

K  Fasiani,  Arch.  Ital.  de  Biol.,  57,  222,  1912. 

"Literature:  A.  Ellinger,  Handb.  d.  Biochem.,  S',  579-581,  1910;  A.  Schit- 
tenhelm, ibid.,  k',  525-528,  1910. 


METHYLATED  PURIN  DERIVATIVES 


167 


CAFFEIN 

CHj— NH— CO 

/         I  /CH, 

CO  C— N< 

\       I       >co 

CH,— NH— C— Nx 


PARAXANTHIN 

CH3— N— CO 


TEEOBROMIN 

N— CO 
/        I  /CH, 

CO         C— N< 

\       I       >co 

— N— C— W 


THEOPHYLLIN 

CH,— N— CO 

/      I 
CO        C— Ns 


CH, 


CH3— N 


--i-N> 


CO         C-N-CH, 
N-C-N/C0 

1-MONOMETHYL- 
XANTHIN 


CH,-N— CO 


CO 


C— Nv 

\      I      >co 

N— C—  W 


7  —  MONOMETHYLXAN- 
THIN  (  =  HETEROXANTHIN) 

N— CO 
CO  C-N-CH, 

\      I    \co 

N-C-N/L/U 


^X 


3  —  MONOMETHYL- 

XANTHIN 

N— CO 

CO  C— Nv 

\      I      >co. 

CHS— N— C— N/ 


It  is  possible  apparently  that  the  demethylation,  how- 
ever, can  proceed  further  and  may  in  the  end  lead  to  the  pro- 
duction of  uric  acid  and  allantoin,  for  which  reason  the 
prohibition  of  coffee,  tea  and  chocolate  is  probably  always 
advisable  in  prescribing  diet  for  a  case  of  gout 58 ;  although 
the  methylxanthins  are  likely  to  increase  the  purins  sooner 
than  the  uric  acid  in  the  urine.  The  methyl  derivatives 
of  xanthin  are  entirely  absent  from  the  urine  of  an  individual 
who  has  abstained  completely  from  coffee  and  tea ;  but  this 


is  not  true  of  epiguanin  I  (NH)c' 


N— CO 


,CH 


C— N<^       i    a  guanin  de- 


N— c— Nx 

rivative  which  cannot  originate  from  any  of  the  known 
purins  of  coffee  and  tea.39  It  is  possible  that  we  are  here 
dealing  with  an  example  of  the  methylation  processes  in 
the  body  which  have  been  previously  considered  (v.  supra, 
p.    132).     Demethylation    of   methylated   xanthin   deriva- 


MA.  Schittenhehn.  Therap.  Monatsch.,  1910,  113;    P.  Fauval,  Compt.  Med., 
142,  1428,  1906;    1^8,  1541,  1909. 

80  M.  Krüger,  Biochem.  Zeitschr.,  15,  361,  1909. 


168  PHYSIOLOGY  OF  PURIN  METABOLISM 

tives  has  been  directly  observed  in  experiments  with  tissue 
pulp.00 

Quantitative  Estimation  of  Uric  Acid. — In  concluding 
the  present  lecture  a  few  words  may  be  devoted  to  enumera- 
tion of  recent  advances  in  the  analysis  of  the  urinary 
purins. 

Besides  the  time-honored  method  of  E.  Ludwig  and 
Salkowski,  which,  as  is  well  known,  depends  upon  precipitat- 
ing the  uric  acid  by  magnesia  mixture  and  ammoniacal  silver 
solution,  the  method  of  Hopkins  has  met  with  the  most 
popularity.  In  the  latter  the  uric  acid  is  thrown  down  by 
ammonia  and  ammonium  chloride  as  ammonium  urate.  The 
uric  acid,  freed  from  the  urate  by  hydrochloric  acid,  may  be 
weighed  or  determined  by  the  Kjeldahl  method.  Folin  and 
Schaffer  have  modified  this  method,  by  titration  of  the  acid 
in  sulphuric  acid  solution  with  permanganate.  According 
to  Eonchese  the  uric  acid  separated  by  the  Hopkins  method 
may  readily  be  titrated  with  a  solution  of  iodine  in  an 
alkaline  medium,  employing  starch  paste  as  an  indicator.61 
Kowarski 62  proposes  to  free  the  uric  acid  from  the  urate  of 
ammonium  precipitated  as  in  the  Hopkins  method,  by  means 
of  hydrochloric  acid,  then  to  wash  with  water  and  alcohol 
until  the  reaction  becomes  neutral,  and  finally  to  titrate  with 
n/50  piperidin  solution  against  Phenolphthalein.  According 
to  Krüger  and  Schmid 6:i  precipitation  of  uric  acid  and  the 
purin  bases  with  copper  sulphate  and  acid  sulphite  of  sodium 
has  proved  useful ;  after  breaking  up  the  precipitate  with 
sodium  sulphide  the  uric  acid  may  be  caused  to  crystallize 
out  by  rendering  the  solution  acid  with  sulphuric  acid ;  by 
which  means  it  may  be  separated  from  the  purin  bases. 
His 's  method  of  uric  acid  estimation  consists  in  acidifying 

60  Brugsch,  Pincussohn  and  Schittenhelm,  cited  in  Handb.  d.  Biochem., 
Jf',  528;  Y.  Kotake,  Zeitschr.  f.  physiol.  Chem.,  57,  378,  1909;  J.  Schmid 
(Breslau),  ibid.,  61,  155,  1910. 

"  A.  Ronchese,  C.  R.  Soc.  de  Biol.,  60,  504,  1906. 

C2A.  Kowarski,  Deutsche  med.  Wochenschr.,  1906,  997. 

6a  J.  Krüger  and  J.  Schmid,  Zeitschr.  f.  physiol.  Chem.,  Ifö,  1,  1905. 


METHOD  OF  ESTIMATING  ALLANTOIN  169 

the  urine  with  hydrochloric  acid,  inoculating  it  with  a  bit  of 
uric  acid  and  subsequently  shaking  the  urine  for  a  long  time 
when  the  salt-like  combined  uric  acid  is  separated,  presum- 
ably completely.  However,  this  method  furnishes  distinctly 
lower  results  than  the  Ludwig-Salkowski  and  other  methods, 
probably  because  it  leaves  complex  uric  acid  combinations 
intact.  It  may,  however,  possibly  serve,  if  more  fully  elab- 
orated, to  separate  the  uric  acid  which  is  in  the  blood  in  loose 
salt-like  form  from  that  in  firmer  combination.64 

Wiechowski's  Method  of  Estimating  Allantoin. — Refer- 
ence has  been  made  to  the  very  great  importance  of 
Wiechowski's  method  of  determining  allantoin,  and  the 
statement  made  that  the  introduction  of  this  method,  which 
had  been  worked  out  very  precisely,  had  determined  the  turn- 
ing point  in  the  historical  development  of  the  study  of  purin 
metabolism.  The  method  consists  first  of  removal  of  all 
substances  from  the  urine  which  can  be  precipitated  by 
means  of  phosphotungstic  acid,  acetate  of  lead  and  acetate 
of  silver,  after  which  the  allantoin  is  thrown  down  by 
mercuric  acetate  with  addition  of  sodium  acetate  after  care- 
ful neutralization.  In  animal  urine  the  nitrogen  content  of 
the  precipitate  may  then  be  directly  determined ;  the  impuri- 
ties in  the  precipitate  being  in  such  small  amount  that  they 
are  scarcely  appreciable  analytically  in  proportion  to  the 
relatively  large  amount  of  allantoin.  However,  in  case  of 
the  very  scant  quantities  of  allantoin  in  human  urine,  the 
conditions  are  quite  different.  In  this  case  simple  nitrogen 
determination  of  the  precipitate  cannot  be  used,  and  it  is 
essential  to  have  recourse  to  purifying  processes  to  enable 
us  to  separate  and  weigh  the  allantoin  in  crystalline  form.65 

MA.  Nicolaier  and  M.  Dohrn,  Deutsch.  Arch.  f.  klin.  Med.,  91,  151,  1907; 
B.  Bloch  (Med.  Clinic  of  W.  His,  Basel),  Deutsch.  Arch.  f.  klin.  Med.,  83,  499, 
1905 ;    Meisenburg,  ibid.,  87,  425,  1906. 

06  W.  Wiechowski,  Hofmeisters  Beitr.,  11,  121-131,  1907;  Biochem. 
Zeitschr.,  25,  446-453,  1910. 


CHAPTER  VIII 
PATHOLOGY  OF  PURIN  METABOLISM 

Having  attempted  in  the  previous  lecture  to  orient  our- 
selves in  relation  to  the  present  status  of  the  theory  of  nor- 
mal purin  metabolism,  we  may  at  once  proceed  to  picture  to 
ourselves  the  nature  of  gout  as  it  is  viewed  to-day.  Quite 
naturally  the  author  prefers  to  limit  the  present  discussion 
to  the  basic  physiological  chemical  problems,  and  would 
therefore  refer  to  the  recent  monographs  on  the  subject  for 
the  various  details,  particularly  those  involving  the  clinical 
symptoms,  the  pathological  anatomy  and  questions  as  to  the 
therapy  concerned  in  this  affection.1 

Increase  of  Uric  Acid  in  the  Blood  of  the  Gouty. — 
The  views  held  as  to  the  nature  of  this  puzzling  anomaly 
of  metabolism  are  so  changing  that  it  is  by  no  means  easy  for 
the  biological  chemist  to  find  a  fixed  point  in  the  flood  of 
phenomena.  Perhaps  such  a  point  of  inception  may  be  rec- 
ognized in  the  increase  of  uric  acid  in  the  blood  in  gouty 
subjects.  It  is  true  that  even  at  the  present  day  there  are 
earnest  persons  who  doubt  whether  uric  acid,  the  local 
depositions  of  which  characterize  the  morphological  picture 
of  the  disease,  is  to  be  looked  upon  as  the  actual  materia 
peccans  of  gout,  and  whether  it  does  not  play  merely  a  col- 
lateral and  secondary  part.  But,  for  at  least  a  half  century, 
the  fact  pointed  out  by  Garrod  in  1848  that  the  blood  of  gouty 
individuals  is  at  times  richer  in  uric  acid  than  that  of  normal 
persons  has  maintained  its  position.  G-arrod's  primitive 
experiment  (he  demonstrated  by  his  "thread  test"  that 
threads  laid  in  blood  serum  to  which  an  acid  was  added 
would,  from  the  crystallization  of  uric  acid,  after  a  time  be 

1  H.  Wiener,  Ergebn.  d.  Physiol.,  2,  377-432,  1903;  O.  Minkowski,  Die  Gicht, 
Vienna,  1903  (in  Nothnagel's  Handb.  d.  spez.  Pathol.)  ;  W.  Ebstein,  Die  Natur 
u.  Behandl.  d.  Gicht,  2d  ed.,  1906 ;  C.  v.  Noorden,  Handb.  d.  Pathol,  d.  Stoff- 
wechsel, 2d  ed.,  2,  138-188,  1907 ;  F.  Umber,  Lehr.  d.  Ernähr,  u.  d.  Stoffwech- 
selkr.,  pp.  262-340,  1909;  A.  Schittenhelm,  Handb.  d.  Biochem.,  If'  529-535, 
1910. 

170 


FORMATION  OF  URIC  ACID  171 

covered  over  with  glistening  crystals)  has  given  place  to 
more  modern  methods.  Yet  the  more  recent  investigators, 
as  Klemperer,  Magnus-Levy  and  Brugsch,  have  confirmed 
his  original  statement  that  uric  acid  is  usually  increased  in 
the  blood  of  the  gouty.  This  holds  good  in  a  remarkable 
manner,  according  to  Brugsch  and  Schittenhelm,2  for  the 
gouty  even  on  purin-f ree  diet ;  from  which  therefore  it  may 
be  inferred  that  the  accumulation  of  the  acid  in  the  blood 
results  from  an  abnormality  in  the  usual  course  of  the 
endogenous  purins  originating  in  tissue  destruction,  inde- 
pendently of  the  dietary  purin  exchange. 

It  was,  however,  early  recognized  that  the  increase  of  uric 
acid  in  the  blood  could  not  by  any  means  be  held  fully  ex- 
planatory of  gout  as  an  entity  of  disease,  precisely  anal- 
ogous increments  being  met  in  other  conditions  entirely 
different  from  gout.  After  exhibition  of  food  rich  in 
nucleins  (as  thymus)  an  alimentary  uriccemia  has  been  ob- 
served; there  is  a  uriccemia  of  endogenous  source  in 
leukaemia,  and,  too,  in  pneumonia,  at  the  time  when  with  the 
exudate  cellular  constituents  are  being  massively  resorbed. 
In  addition,  a  retention  uriccemia  is  recognized  in  conditions 
of  functional  renal  disturbance,  as  in  chronic  affections  of 
the  kidneys  of  all  types  and  their  sequel,  uraemia.3 

It  is  to  be  presumed,  therefore,  that  the  increase  of  uric 
acid  in  the  blood  of  gouty  patients  is  to  be  ascribed  either  to 
an  increased  entrance  or  a  diminished  escape  of  the  material. 

Question  of  Increase  in  the  Formation  of  Uric  Acid. — 
For  a  long  time  the  first  of  these  possibilities  was  the 
dominating  one  in  discussions  of  the  problem.  Many  agreed 
that  the  fundamental  point  in  the  disease  is  to  be  looked  for 
in  an  increase  in  the  destruction  of  the  tissue  nucleins.  As  a 
matter  of  fact,  however,  there  was  absolutely  no  basis  for 

'  Th.  Brugsch  and  A.  Schittenhelm,  Zeitschr.  f .  exper.  Ther.,  4,  438,  1907 ; 
B.  Bloch  (Med.  Clinic,  Basel),  Zeitschr.  f.  physiol.  Chem.,  51,  472,  1907;  Th. 
Brugsch   (F.  Kraus'  Clinic),  Berlin  klin.  Wochenschr.,  1912,  No.  34. 

•Literature  upon  the  Various  Forms  of  Uricaemia:  A.  Schittenhelm, 
Handb.  d.  Biochem.,  k' ,  529-540,  1910. 


172  PATHOLOGY  OF  PURIN  METABOLISM 

assuming  that  the  primary  factor  in  the  pathology  of  gout 
is  to  be  ascribed  to  cellular  destruction.  A  uniform  increase 
of  phosphorus  elimination  was  not  to  be  found  in  gout, 
although  necessarily  this  should  be  coincident  with  any  in- 
crease in  the  decomposition  of  nucleins.  It  cannot,  of  course, 
be  denied  that  in  the  course  of  gout,  just  as  in  many  other 
affections,  there  does  at  times  take  place  an  exaggerated  de- 
struction of  tissue.  This  is  brought  out  in  the  carefully 
conducted  studies  of  the  protein  metabolism  in  gout  by 
Magnus-Levy.  We  frequently  refer  to  a  "  toxogenic  protein 
decomposition"  in  acute  gouty  exacerbations,  and  often  rec- 
ognize in  the  paroxysms  of  gout  that  a  period  of  nitrogen 
retention  succeeds  this  increased  protein  decomposition.  In 
gouty  individuals  it  may  often  be  observed  that  periods  of 
nitrogen  retention  and  of  nitrogen  deficit  are  likely  to  occur 
intermittently  without  any  regularity ;  and  v.  Noorden  be- 
lieves "that  in  a  subject  of  gout  even  in  the  intervals  there 
exist  (specific1?)  gout-substances,  which  exert  now  more, 
now  less  harmful  influence  upon  protein  decomposition  just 
as  in  other  chronic  affections."4  However,  the  author  is 
unable  to  appreciate  the  least  reason  for  forcing  these  points 
into  the  foreground  of  the  general  problem.5 

There  is  therefore  no  basis  for  seeking  the  cause  of  gout 
in  an  increased  formation  of  uric  acid  from  oxidation  pro- 
cesses ;  but  there  is  actually  less  reason  for  assuming  that 
it  is  to  be  met  in  an  increased  synthetic  formation  of  uric 
acid,  for  we  have  seen  that  while  this  method  plays  an  im- 
portant role  in  birds  and  reptiles  we  have  no  right  to  assert 
its  existence  in  the  mammalian  economy. 

If  the  uric  acid  accumulation  in  the  blood,  character- 

4  Literature  upon  Protein  Exchange  in  Gout :  K.  v.  Noorden,  v.  Noorden's 
Handb.  d.  Pathol,  d.  Stoffwechsels,  2d  ed.,  2,  139-143,  1907. 

5  That,  however,  an  increased  cellular  destruction,  as  induced  experi- 
mentally, for  example,  by  exposure  to  Röntgen  rays,  is  capable  of  raising  the 
hsemic  content  of  uric  acid  in  a  gouty  subject  and  of  precipitating  a  gouty 
paroxysm,  may  be  inferred  from  the  observations  of  P.  Linsen  (Romberg's 
Clinic)  :    Therap.  d.  Gegenw.,  1,9,  159,  1908. 


REDUCTION  OF  URIC  ACID  DECOMPOSITION      173 

istically  met  in  gout,  in  conformity  with  the  above  statements 
is  not  due  to  an  increase  in  formation,  the  logical  conclusion 
is  that  it  must  be  dependent  upon  some  interference  or  pro- 
longation in  the  elimination  of  uric  acid. 

Question  of  Reduction  of  Uric  Acid  Decomposition  in 
Gout. — The  elimination  of  uric  acid  from  the  blood  may? 
doubtless,  be  accomplished  by  its  destruction  by  oxidation. 
This,  as  has  been  seen,  occurs  physiologically  in  the  experi- 
ment animals  in  laboratory  investigation  upon  this  point,  the 
uric  acid  being  changed  into  allantoin.  This,  however,  is  not 
true  of  man,  in  whom  the  latter  process  of  conversion  takes 
place  only  in  a  very  minor  degree.  At  once,  then,  a  question 
which  has  been  discussed  in  the  previous  lecture  recurs.  Is 
uric  acid  in  man  to  be  looked  upon,  as  Wiechowski  believes,  as 
an  end-product  of  metabolism;  or  is  it,  as  Brugsch  and  Schit- 
tenhelm  and  Burian  opine,  subject  in  some  degree  in  man  to 
further  catabolic  change,  perhaps  to  the  formation  of  urea  ? 
In  the  author's  opinion  Wiechowski 's  arguments  are  entirely 
obvious ;  and  in  consonance  with  this  view  he  would  con- 
clude that  the  basis  of  gout  cannot  be  referred  to  a  reduction 
in  the  ability  of  the  body  to  decompose  uric  acid  by  oxida- 
tion, because  this  process  cannot  physiologically  be  an  im- 
portant one  in  the  human  body.  The  author  appreciates 
thoroughly  that  others  have  different  opinions  upon  these 
matters ;  but,  as  was  remarked  in  a  previous  lecture,  every 
man  can  observe  only  with  his  own  eyes  and  think  only  with 
his  own  brain.  Fortunately,  every  problem  in  the  natural 
sciences  is  bound  sooner  or  later  to  come  to  a  stage  where  a 
natural  end  is  fixed  for  all  subjective  conceptions  and  where 
the  actual  state  of  affairs  objectively  viewed  assumes  a  more 
or  less  obvious  aspect. 

If  then  it  is  correct,  in  accordance  with  the  author's  belief, 
that  in  gout  we  are  not  dealing  with  a  reduction  of  uric  acid 
decomposition,  there  is  obviously  only  one  possible  explana- 


174  PATHOLOGY  OF  PURIN  METABOLISM 

tion  remaining:  that  in  some  way  and  from  some  cause  the 
excretion  of  uric  acid  is  itself  at  fault. 

Curve  of  Uric  Acid  Excretion  in  Acute  Gouty  Exacerba- 
tions.— In  review  of  the  literature  of  gout  two  groups  of  phe- 
nomena (apparently  beyond  question  of  doubt)  stand  out 
prominently,  which  may  be  held  to  indicate  that  faults  of 
excretion  play  an  actually  important  part  in  the  pathology  of 
gout.  These  are  the  characteristic  curve  of  urinary  excre- 
tion of  uric  acid  in  acute  gouty  exacerbations  and  the  fact  of 
the  delayed  transformation  of  nucleins  in  the  gouty  subject. 

Primarily,  in  reference  to  the  first  of  these  features, 
Friedrich  Umber  may  be  cited  as  a  clinical  witness.  This 
authority  says  in  his  valuable  text-book  upon  nutrition  and 
the  diseases  of  metabolism:  "The  curve  of  uric  acid  excre- 
tion in  the  gouty  subject  on  purin-free  diet  is  so  character- 
istic in  the  periods  of  exacerbation  as  to  be  of  distinctly 
pathognomonic  value.  The  essential  endogenous  curve  of 
uric  acid  sinks,  as  His  has  pointed  out,  immediately  before 
the  paroxysm  to  a  still  lower  level  (which  I  may  speak  of 
as  an  anacritical  stage  of  depression),  to  quickly  increase 
as  soon  as  the  paroxysm  has  begun  (el  uric  acid  wave,  accord- 
ing to  E.  Pfeiffer,  who  first  observed  this  point),  and  reaches 
its  acme  on  the  second  or  third  day;  after  which  with  the 
gradual  disappearance  of  the  gouty  paroxysm  it  again  sinks 
into  a  second  or  postcritical  stage  of  depression  succeeding 
the  paroxysm.  .  .  .  This  course  of  the  endogenous  purin 
curve  may,  it  is  true,  ...  be  modified  by  frequently 
recurring  gouty  exacerbations ;  but  aside  from  this  it  is  of 
decided  significance  as  a  feature  in  differential  diagnosis. ' ' 6 

Delayed  Nuclein  Exchange  in  the  Gouty. — Along  with 
this  fact  of  the  damming  back  of  the  uric  acid  and  its  break- 
ing through  the  dam  in  some  degree  in  the  acute  paroxysms 

•  F.  Umber,  Lehrb.  d.  Ernährung  u.  d.  Stoffwechselkrankheiten,  p.  269, 
Berlin  and  Vienna,  Urban  and  Schwarzenberg,  1909. 


GOUT  AND  NEPHRITIS  175 

of  the  disease,  we  may  probably  regard  as  one  of  the  most 
important  advances  in  our  appreciation  of  the  patholo- 
genesis  of  this  anomaly  of  metabolism  the  recognition  that 
conversion  of  nucleins  is  slow  in  the  course  of  gout. 

The  fact  that  the  gouty  individual  after  ingestion  of 
purin-containing  food  shows  a  delayed  excretion  of  uric  acid 
has  been  proved  by  a  number  of  investigations ; 7  he  does  not, 
as  a  normal  person,  throw  off  his  excess  of  uric  acid  in  a  short 
time,  but ' '  spreads  out ' '  the  excretion  over  a  number  of  days. 
This  feature  is  sufficiently  characteristic  to  have  come  into 
employment  in  diagnosis  of  gouty  affections,  the  uric  acid 
excretion-curve  being  kept  under  observation  after  addition 
of  a  given  quantity  of  nucleinic  acid  to  the  food.8 

Gout  and  Nephritis. — This  has  suggested  the  thought  that 
the  cause  of  this  uric  acid  stagnation  may  reside  in  the  kid- 
neys; the  frequent  coincidence  of  nephritis  (particularly 
contracted  kidneys)  and  gout  was  emphasized,  and  the  point 
made  that  both  alcoholism  and  lead  poisoning  may  play  an 
important  part  in  the  etiology  of  both  affections.  C.  v.  Noor- 
den  in  his  valuable  monograph  upon  gout 9  very  properly 
says  that  it  is  not  right  to  do  violence  to  the  facts  by  assum- 
ing in  a  case  which  presents  no  other  evidence  of  nephritis  a 
"latent  nephritis"  to  explain  the  gouty  uric  acid  stagnation. 
When  one  remembers  the  fact  that  usually  the  kidneys  of  a 
case  of  Bright 's  disease  perform  effectually  the  uric  acid 
excretion  required  of  them,  it  is  clearly  evident  that  in  sup- 
posing that  the  nephritis  causes  the  gout  there  has  been  a 
confusion  of  cause  and  effect;  actually  the  reverse  is  some- 
times the  truth. 

'  Vogt,  Reach,  Soetbeer,  Kaufmann  and  Mohr,  L.  Pollak,  Brugsch,  Hirsch- 
stein, Lesser,  Bloch,  Schittenhelm,  Rotky  and  others.  For  Literature,  consult 
Umber,  1.  c,  p.  271;  A.  Schittenhelm,  Handb.  d.  Biochem.,  4',  pp.  531,  532,  1910. 

8H.  v.  Hösslin  and  K.  Kato  (Med.  Clinic,  Halle),  Deutsche  Arch.  f.  klin. 
Med.,  99,  301,  1910. 

•  C.  v.  Noorden,  Handb.  d.  Pathol,  d.  Stoffwechsels,  2d  ed.,  2,  pp.  164,  165, 
1907. 


176  PATHOLOGY  OF  PURIN  METABOLISM 

Uric  Acid  Retention. — Umber  has  observed  that  gouty 
individuals  may  at  times  retain  all  of  a  given  amount  of  uric 
acid  which  has  been  injected  intravenously,  at  times  may 
excrete  it  in  small  fractions ;  while  a  normal  individual  un- 
der similar  circumstances  eliminates  it  completely.10  (Simi- 
lar retention  has  been  met  only  in  individuals  suffering  from 
chronic  lead  poisoning  and  pronounced  alcoholism,  condi- 
tions which  if  not  allied  to  gout  are  certainly  allied  to  a 
disposition  toward  gout.)  A  positive  statement  like  this  is 
surely  of  more  force  than  the  negative  results  of  v.  Bene- 
zur,11  who,  after  intramuscular  injection  of  uric  acid  in  a 
gouty  case,  found  that  it  appeared  promptly  in  the  urine. 
Apparently,  too,  an  individual  with  renal  disease  excretes 
his  uric  acid  better  on  the  whole  than  does  a  gouty  subject 
with  sound  kidneys.12  Observations  like  those  of  Schmoll, 
Magnus-Levy,  Vog-t,  Reach  13  and  Bloch,14  who  state  that 
after  feeding  thymus  to  gouty  persons  they  found  far  less 
uric  acid  in  the  urine  than  in  case  of  normal  persons,  seem 
to  have  practically  but  a  single  meaning ;  and  the  acute  out- 
bursts of  the  disease,  which  were  repeatedly  brought  on  by 
feeding  thymus  in  cases  of  chronic  gout,  and  undoubtedly 
are  to  be  thought  of  as  experiments  having  identical  bearing, 
are  especially  impressive. 

Affinity  of  the  Tissues  for  Uric  Acid. — If  the  kidneys 
are  not  to  be  looked  upon  as  responsible  for  the  scanti- 
ness of  purin  excretion  in  gout,  search  must  be  made  else- 
where. The  author  believes  Umber  is  correct  when  he 
states  that  an  increased  affinity  of  the  tissues  for  uric 

10  F.  Umber  and  H.  Retzlaff  (Altona),  27th  Congress  of  Internists,  Wies- 
baden, 1910,  p.  436. 

u  G.  v.  Benczur  (See.  Med.  Clinic,  Berlin),  Zeitschr.  f.  exper.  Pathol.,  7, 
339,  1909. 

12  Cf.  Tollens,  Zeitschr.  f.  physiol.  Chem.,  53,  164,  1904. 

13  F.  Reach  (F.  v.  Müllers  Clinic,  Basel),  Münchener  med.  Wochenschr., 
1902,  No.  29 ;  vide  there  Literature. 

"B.  Bloch  (Med.  Clinic,  Basel),  Zeitschr.  f.  physiol.  Chem.,  51,  473,  1907. 


AFFINITY  OF  TISSUES  FOR  URIC  ACID  177 

acid  is  the  real  reason  for  the  diminished  urinary  excre- 
tion of  purins,  for  the  retention  of  uric  acid  in  the  blood, 
lymph  and  tissues  (which  may  lead  to  gross  uratic  deposits 
in  the  body),  and  for  the  gouty  exacerbation  after  a  purin- 
containing  diet.  "To  attempt  to  refer  the  entire  complex 
of  gout  completely  to  faults  in  the  catabolism  of  nucleinic 
acid  due  to  insufficiency  in  the  enzymes  concerned,"  says 
Umber,15 ' '  as  Schittenhelm  and  Brugsch  recently  declared,  is 
not  satisfactory,  entirely  apart  from  the  fact  that  Wiechow- 
ski,  in  the  course  of  his  studies  as  to  the  possibility  of  uric 
acid  decomposition  in  the  human  body,  was  never  able  to 
detect  any  uricolysis  worth  mentioning.  If  we  were  to  refuse 
the  idea  of  retention  in  the  tissues,  it  would  be  a  particularly 
difficult  thing  to  understand  why  gouty  patients  do  not  sim- 
ply expel  by  a  compensatory  hyperexcretion  the  uric  acid 
which  is  accumulated  from  a  supposed  failure  of  uricolysis ; 
precisely  as  in  leukaemia  the  patient  compensates  simply  by 
an  exaggerated  excretion  of  the  excessive  uric  acid  which  is 
mobilized  in  the  body  from  the  excessive  purin  decomposi- 
tion. In  the  gouty  individual  there  must  exist  some  cause 
which  makes  a  compensatory  uric  acid  excretion  impossible; 
and  that  is  plainly  a  retention-affinity  of  the  tissues,  because 
of  which  the  uric  acid  is  actually  held  in  the  tissues." 

The  impression  grows  on  one  that  this  hitherto  little  con- 
sidered factor,  of  an  increased  affinity  of  the  tissues  for  uric 
acid  in  the  gouty  subject,16  is  very  much  closer  to  the  real 
kernel  of  the  gout  problem  than,  for  example,  the  question 
of  the  fixation  of  uric  acid  in  the  blood,  about  which  there 
has  been  so  much  contention  and  with  which  of  necessity  we 
are  compelled  at  least  to  some  little  extent  to  concern 
ourselves. 

15  F.  Umber,  Lehrbuch  der  Ernährung  und  der  Stoffwechselkrankheiten, 
p.  273,  1909. 

M  Cf.  F.  Umber  and  K.  Retzlaff,  1.  c. 

12 


178  PATHOLOGY  OF  PURIN  METABOLISM 

In  what  form  does  the  uric  acid,  a  substance  relatively 
difficult  of  solution  when  free,  exist  when  it  is  dissolved  in  the 
blood? 

Alkali  Compounds  of  Uric  Acid. — One  would  undoubtedly 
first  think  of  the  uric  acid  as  being  in  some  alkali  combina- 
tion for  its  solution  in  the  circulating  blood.  What  are  the 
known  types  of  alkali-compounds  of  uric  acid  I  First  may  be 
mentioned  combinations  of  the  type  of  sodium  monourate 
(C5H.3N4O3.Na)  and  of  sodium  biurate  (C5H2N403.Na2) ;  but 
it  should  also  be  noted  that  the  readily  soluble  biurate  of 
sodium  cannot  exist  in  the  presence  of  the  haemic  carbonic 
acid.  Besides  these  the  existence  of  combinations  of  the 
type  C5H3N403Na.C5H4N403  is  assumed.  These  last  have 
been  called  " quadriurates ' '  by  Bence- Jones  and  Roberts; 
but  the  name  should  for  logical  reasons  be  changed  to 
'  'hemiurates. ' '  The  assumption  that  these  (met  with  in  the 
latericious  urinary  sediment  and  in  the  excrement  of  birds 
and  snakes)  correspond  structurally  to  a  fixed  molecular 
proportion  (one  atom  of  sodium  to  two  molecules  of  uric 
acid)  is  not  confirmed  by  recent  investigations.  In  all  prob- 
ability the  quadriurates  are  in  reality  a  mixture  of  primary 
urate  and  free  uric  acid,  which  is  usually  fairly  constant 
under  uniform  external  conditions,  thus  necessarily  suggest- 
ing the  formation  of  mixed-crystals  (solid  solutions).17 

Part  Taken  by  Changes  in  Alkalescence. — In  the  older 
conceptions  of  the  pathology  of  gout  the  hypothesis  that 
separation  of  the  uric  acid  from  the  blood  into  the  tissues 
was  due  to  a  lowering  of  the  alkalescence  of  the  blood  or  of 
the  tissue-juices,  was  maintained  strongly.  In  spite  of 
the  fact  that  one  of  the  greatest  experts  on  gout,  C.  v. 
Noorden,18  long  since  characterized  all  theorizations  upon 

17  W.  E.  Ringer  (Physiol.  Instit.,  Utrecht.),  Zeitschr.  f.  physiol.  Chem.,  67, 
332,  1910;  75,  13,  1911;  R.  Kohler  (His's  Clinic,  Berlin),  ibid.,  70,  360.  1911; 
72,  169,  1911;   O.  Rosenheim,  ibid.,  71,  272,  1911. 

18  C.  v.  Noorden,  Handb.  d.  Pathol,  d.  Stoffwechsels.,  2d  ed.,  2,  168,  169,  1907. 


LACTAM  AND  LACTIM  FORMS  OF  URATES         179 

the  interrelations  of  blood  alkalescence,  local  changes  of 
tissue  alkalescence,  and  gouty  deposits  as  ' '  swinging  loosely 
in  the  air,"  it  will  doubtless  take  a  very  long  time  before 
physicians  will  stop  making  their  patients  believe  that  their 
malady  is  due  to  too  much  acid  in  the  blood,  and  that  nothing 
but  continued  drinking  of  this  or  that  alkaline  water  (n.b.,  to 
be  taken  at  the  spring)  can  possibly  eradicate  this  acid.  Un- 
fortunately there  are  many  instances  in  the  chemical  physi- 
ology of  metabolism  in  relation  with  which  material  interests 
directly  interfere  with  the  acceptance  of  scientific  facts.  The 
opportunity  should  not  be  passed  over  here  to  point  out  too, 
how  irrational  it  is  to  try  to  draw  any  sort  of  conclusions 
from  the  analysis  of  a  single  specimen  of  urine  (whether 
from  its  "degree  of  acidity"  or  its  "content  of  uric  acid") 
for  application  in  the  diagnosis  of  gout  or  in  the  recognition 
of  improvement  or  regression  of  this  condition.  This  is  pos- 
sible only,  and  then  with  great  caution,  from  a  long  series  of 
careful  quantitative  examinations  during  purin-free  diet,  or 
perhaps  in  the  way  that  C.  v.  Noorden  tests  the  limits  of 
tolerance  of  his  patients,  by  increasing  dosage  of  purin  and 
determining  how  much  purin  the  subject  can  handle  without 
manifesting  a  retention  in  the  daily  balance-test.  When 
a  physician  allows  a  quantitative  analysis  to  be  made  of  any 
arbitrarily  collected  specimen  of  urine  of  his  patient  and 
then  makes  a  diagnosis  of  presence  or  absence  of  a  "gouty 
diathesis"  after  a  glance  at  the  list  of  data  of  the  analysis, 
he  is  really  not  proving  by  his  actions  his  possession  of  diag- 
nostic acumen  as  much  as  he  is  laying  bare  his  total 
ignorance  of  biochemical  matters. 

Lactam  and  Lactim  Forms  of  Urates. — Among  the  fac- 
tors to  be  considered  in  reference  to  the  solubility  of  uric 
acid  in  the  blood  and  its  removal  therefrom,  is  the  important 
point,  first  discovered  by  Gudzent,  that  uric  acid  forms  two 
series  of  primary  salts,  and  that  one  of  these,  a  readily 
soluble,  instable  urate,  has  the  tendency  in  its  solutions  to 
change  over  into  the  second,  a  less  soluble  (about  one-third). 


180  PATHOLOGY  OF  PURIN  METABOLISM 

stable  urate.  Following  the  conceptions  originating  with 
Emil  Fischer  in  relation  to  the  tautomeric  forms  of  uric  acid, 
we  may  suppose  that  we  have  here  a  transformation  of 
instable  lactamurate  into  stable  lactimurate : 

LACTAM  FORM  LACTIM  FORM 

NH-CO  N=C(OH) 

/I  /         I 

co         c— nh >  c(oh)        c-nh 

\h-c-nh>co  %n-c-nh>c(°h)- 

A  transformation  of  this  kind,  from  the  instable  to  the 
stable  form,  seems  to  take  place  in  the  circulating  blood.19 
It  is  supposed  that  because  of  the  difference  in  solubility  of 
these  two  interchangeable  forms  of  monourate,  the  blood  of 
gouty  individuals  must  at  times  represent  a  supersaturated 
solution  of  uric  acid,  which  can  only  gradually  resume  its 
equilibrium  by  removal  of  urates  by  crystallization.  That 
gouty  blood  is  not  comparable,  however,  at  least  not  in  all 
conditions,  to  a  supersaturated  solution  of  uric  acid  is  evi- 
dent from  Klemperer's  results,  showing  that  the  blood  of  a 
gouty  subject  is  capable  of  dissolving  considerable  amounts 
more  of  uric  acid.  Apparently  it  were  best  to  hold  that  the 
subject  is  not  at  present  proved  to  be  a  matter  of  pathological 
importance. 

Nucleinic  Acid  Combination  With  Uric  Acid. — From 
the  observation  that  uric  acid  can  no  longer  be  precipi- 
tated either  by  acetic  acid  or  by  alkaline  ammonio-silver- 
magnesia  mixture  from  a  mixed  solution  of  uric  acid  and 
nucleinic  acid,  Minkowski  has  held  that  it  is  probable 
"that  uric  acid  primarily  exists  in  the  blood  and  the  tissue 
juices  in  combination  with  nucleinic  acid,  and  that  not  only 
the  conversion  of  the  purin  bases  into  uric  acid,  but  also 
the  solubility  and  transportation  as  well  as  the  further 
changes  of  the  uric  acid  in  the  living  body  is  regulated  by 


18  G.  Gudzent   (His's  Med.  Clinic,  Berlin),  Zeitschr.  f.  physiol.  Chem.,  60, 
38,  1909;    63,  455,  1909;    Centralbl.  f.  Stoffw.,  5,  289,  1910. 


CONDITIONS  OF  SOLUBILITY  OF  URIC  ACID       181 

this  linking  with  a  nucleinic  acid  rest. " 20  It  has  been  sup- 
posed, too,  that  uric  acid  by  being  linked  with  nucleinic  acid 
is  protected  to  a  certain  degree  from  oxidation  in  the  body.21 
It  may  be  remarked  with  direct  reference  to  this  last  state- 
ment, that,  if  Wiechowski's  results  are  to  be  accepted,  there 
is  every  reason  to  doubt  whether  uric  acid  is  open  to  oxida- 
tion in  the  human  economy ;  it  would  therefore  have  no  need 
of  protection  by  the  nucleinic  acid  to  insure  its  escape  from 
combustion.  Then,  too,  aside  from  the  traces  found  in  the 
urine,  we  have  not  the  least  basis  for  supposing  that  nucleinic 
acid  is  actually  present  in  the  circulating  blood.22  Nor  is  the 
prevention  of  precipitation  shown  by  uric  acid  in  the  pres- 
ence of  nucleinic  acid  to  be  looked  upon  as  at  all  remarkable ; 
it  is  not  necessarily  indicative  of  a  true  acid  combination 
with  nucleinic  acid.23  Such  inhibition  of  precipitation  is 
rather  to  be  referred  to  the  general  group  of  variations  of 
solubility  which  are  manifested  by  crystalloid  substances  in 
the  presence  of  all  sorts  of  colloids 

Complex  Conditions  of  Solubility  of  Uric  Acid  in  Rela- 
tion to  the  Uric  Acid  Diathesis. — Complex  phenomena  of 
solubility  of  this  type  are  to  be  seriously  considered  in  con- 
nection with  the  uric  acid  of  the  circulating  blood.  The 
nucleinic  acid  is  not  alone  important ;  the  general  mass  of 
blood  proteins  are  particularly  to  be  thought  of.  It  has  been 
stated  that  uric  acid  is  much  more  soluble  in  serum  than  in 
pure  water.24  In  the  urine,  again,  the  solubility  of  the  uric 
acid  is  largely  influenced  by  the  presence  of  urea  and  diso- 
dium  phosphate  (Na2H.P04),  and  relation  of  this  to  monoso- 
sodium  phosphate  (NaH2P04).25  There  is  no  doubt  of  the 
importance  of  such  interrelations,  too,  in  the  formation  of 

20  O.  Minkowski,  Die  Gicht,  in  Nothnagel 's  Handb.  d.  spez.  Pathol.,  pp.  189, 
190,  1903. 

21 Y.  Seo  (Minkowski's  Clinic,  Greifswald),  Arch.  f.  exper.  Pathol.,  58,  75, 
1908. 

a  Th.  Brugsch,  Zeitschr.  f.  exper.  Pathol.,  6,  278,  1909. 

23  A.  Schittenhelm,  Zeitschr.  f.  exper.  Pathol.,  7,  110,  1910. 

24  A.  E.  Taylor,  Jour,  of  Biol.  Chem.,  1,  177,  1905. 

25  Investigations  of  Pfeiffer,  Rudel,  Ritter,  Strauss  and  others. 


182  PATHOLOGY  OF  PURIN  METABOLISM 

renal  and  cystic  calculi,  the  "uratic  diathesis,"  as  well  as  in 
the  formation  of  uric  acid  deposits  in  the  tissues.  (It  may  be 
casually  added  that  Virchow,  however,  long  ago  expressed 
doubt  of  the  existence  of  any  close  relation  between  gout  and 
the  genesis  of  urinary  concretions ;  and  at  the  present  time 
there  are  metabolic  pathologists  of  wide  experience,  like  C.  v. 
Noorden,  G.  Klemperer  and  F.  Umber,  who  believe  that  we 
are  not  justified  in  looking  upon  nephrolithiasis  as  the  result 
of  uric  acid  accumulation  in  the  blood  or  in  the  tissues,  and 
that  it  would  be  better  to  drop  entirely  the  popular,  very 
comprehensive  and  very  much  misused  term  of  "the  uric 
acid  diathesis.")  2Ü  Although  the  importance  of  these  com- 
plex conditions  of  solubility,  as  they  prevail  among  colloid 
and  crystalloid  substances  in  the  animal  juices,  may  be  ac- 
cepted in  relation  to  the  formation  of  uric  acid  sediments  and 
concretions,  there  is  no  real  reason  for  seeking  the  explana- 
tion of  gout  in  this  sphere.  We  may  see  one  sign  of  progress 
in  the  fact  that  at  the  present  we  have  no  appreciation  of  a 
sharp  distinction  between  "loosely  combined"  and  "fixed" 
uric  acid  (Pfeiffer  for  one  tried  to  bring  out  such  a  differ- 
entiation by  means  of  niters  charged  with  uric  acid,  on  which 
gouty  urines  gave  up  a  part  of  their  uric  acid).  In  our 
modern  conceptions  of  physico-chemical  solution-interrela- 
tions there  is  no  longer  room  for  such  schematic  representa- 
tions and  for  different  kinds  of  uric  acid  fixation.  That 
we  know  but  incompletely  the  individual  physico-chemical 
factors  which  determine  the  "fixedness"  of  uric  acid 
combination,  is  quite  another  matter. 

Localization  of  the  Uric  Acid  Depositions. — The  rea- 
son for  localization  of  the  uric  acid  deposits  in  certain 
positions  of  predilection  as  cartilages,  joint  capsules,  ten- 
dons, muscles  and  skin  is  directly  related  with  the  ques- 
tion of  the  complex  conditions  of  solubility  of  uric  acid. 

w  Literature  upon  Uratic  Diathesis :  F.  Umber,  Lehrbu.  d.  Ernährung  und 
Stoffwechselkrankheiten,  pp.  350-356,  1909;  cf.  on  the  contrary  Neubauer, 
Internat.  Kongr.,  Wiesbaden,  1911. 


LOCALIZATION  OF  URIC  ACID  DEPOSITIONS      183 

Probably  special  importance  for  the  interpretation  of  the 
general  problem  may  be  attributed  to  a  discovery  made  in 
Hofmeister 's  laboratory27  that  when  thin  sections  of  car- 
tilage are  left  for  some  hours  in  a  solution  of  sodium  urate 
they  will  take  up  uric  acid.  The  degree  of  concentration  of 
the  urate  solution  is  diminished ;  and  at  the  same  time  when 
the  sections  of  cartilage  are  directly  inspected  they  fre- 
quently show  white  foci  and  diffuse  opacities  of  uric  acid 
deposits.  The  great  affinity  of  normal  cartilage  for  uric 
acid  is  manifested  by  the  fact  that  when  large  amounts  are 
introduced  into  the  peritoneal  cavity  in  rabbits,  the  acid 
may  often  be  detected  by  the  murexide  reaction  in  the  car- 
tilages although  not  apparent  in  other  tissues.  The  ac- 
cumulation of  uric  acid  in  cartilage  in  states  of  increase  of 
uric  acid  in  the  blood  may  be  explained  in  the  same  way. 
The  well-known  theory  of  Ebstein  that  the  dissolved  uric 
acid  infiltrating  the  tissues  acts  primarily  to  produce  an 
inflammation  and  that  an  antecedent  necrosis  precedes  the 
deposition  of  the  uric  acid  is  no  longer  to  be  accepted  in  the 
light  of  the  above  outlined  discovery.  That  an  excess  of 
purins  in  the  body  fluids  may  produce  inflammatory  changes 
is  not  to  be  denied ;  confirmation  may  be  seen  in  a  number  of 
observations,  as  that  of  Levinthal,28  who,  in  a  personal  ex- 
periment, injected  half  a  gram  of  xanthin  (dissolved  in 
piperazin)  into  his  cubital  vein,  and  a  few  days  later,  after 
a  moderate  strain  upon  the  limbs  from  dancing,  he  was  sud- 
denly seized  with  a  fairly  acute  painful  attack  in  one  of  his 
knees,  attended  with  some  swelling  and  local  heat.  Deposi- 
tions may  form  in  the  tissues,  however,  as  shown  by  nu- 
merous observations  upon  gradually  developing  tophi  ex- 
hibiting no  inflammatory  reactions,  entirely  independently 
of  any  antecedent  necrosis. 

27  M.  Almagia  (Instit.  of  Physiol.  Chem.,  S'trassburg) ,  H'ofmeister's  Beitr., 
7,  4G6,  1906. 

23  W.  Levinthal  (F.  v.  Mailer's  Clinic,  Berlin),  Zeitschr.  f.  physiol.  Chem* 
77,  273,  1912. 


184  PATHOLOGY  OF  PURIN  METABOLISM 

Alkalinity  of  the  Tissues  in  Relation  to  Uric  Acid  De- 
posit.— It  is  difficult  to  decide  at  present  to  what  extent 
physical  f actors,  in  contrast  to  chemical  factors,  are  involved 
in  increasing  the  absorbing  power  of  individual  types  of  tis- 
sue for  uric  acid.  We  are  unquestionably  here  again  dealing 
with  a  very  complex  problem  of  physical  chemistry.  It  has 
been  stated,  for  example,  that  aminoacids  tend  to.  inhibit  the 
absorption  of  uric  acid  by  cartilage.29  But,  on  the  other 
hand,  monourates  are  separated  from  uric  acid  solutions, 
and  in  the  same  way  urates  deposit  in  the  tissues  the  more 
readily,  apparently,  the  higher  the  proportion  of  sodium 
present.  Van  Loghem 30  has  from  this  suggested  that  the 
predilection  of  cartilage  and  connective  tissue  for  uric  acid 
bears  some  relation  to  the  large  amounts  of  sodium  contained 
by  these  tissues;  and  he  suggested  that  the  formation  of 
tophi  might  be  restricted  by  the  use  of  hydrochloric  acid  or 
increased  by  alkalies.  It  is  the  same  old  story!  At  any 
rate  one  can  derive  this  one  point  from  it:  The  constant 
effort  to  favorably  influence  gout  by  flooding  the  body  with 
" curative"  alkaline  waters  is  without  the  least  theoretical 
foundation.  ' '  That  by  the  use  of  certain  spring  waters  gout 
can  be  therapeutically  influenced,"  says  Umber,31  "is  at- 
tested by  a  century  of  practice.  But  it  is  practically  proven 
that  the  essential  reason  for  this  fact  does  not  exist  in  any 
immediate  influence  of  the  inorganic  constituents  of  these 
waters  upon  the  disturbances  of  purin-metabolism  in  gout. 
The  importance  of  the  thorough  flushing  of  the  body,  in  which 
even  Garrod  believed  the  pith  of  mineral  water  treatment 
lies,  the  regulated  life  of  the  patients,  their  isolation,  and, 
not  the  least,  the  intelligent  interest  of  specially  trained 

28  Th.  Brugsch  and  J.  Citron  (F.  Kraus's  Clinic,  Berlin),  Zeitschr.  f.  exper. 
Pathol.,  5,  401,  1908. 

80  Van  Loghem  (Amsterdam),  Deutsche  Arch.  f.  klin.  Med.,  85,  416,  1906; 
Centralbl.  f.  Stoffw.,  1907,  244;  consult  also  Roberts,  His  and  Paul,  Gudzent, 
E.  d'Agostino:  Rendic.  della  Societä  Chim.  ItaL,  2,  fasc.  6,  1910. 

31 F.  Umber,  Lehrbu.  d.  Ernährung  und  Stoffwechselkrankheiten,  p.  329, 
1908. 


ATTEMPTS  TO  PRODUCE  GOUT  EXPERIMENTALLY    185 

physicians  in  their  little  and  their  great  complaints, — all 
this  in  the  methods  of  a  health  resort  for  the  gouty  is  a  more 
important  therapeutic  factor  than  the  minerals  that  are 
contained  in  the  waters." 

Attempts  to  Produce  Gout  Experimentally. — Research 
upon  the  nature  of  gout  would  surely  be  in  position  to 
show  more  rapid  progress,  were  it  not  that  experimental 
attempts  to  produce  this  fault  of  metabolism  have  thus 
far  always  proved  failures.  The  part  taken  by  uric  acid 
in  avian  metabolism  (in  birds  the  bulk  of  nitrogen  ex- 
creted appears  as  uric  acid,  and  in  them  the  latter  is  without 
doubt  formed  synthetically)  is  so  fundamentally  different 
from  its  role  in  the  economy  of  man  and  the  mammalia,  that 
it  is  decidedly  difficult  to  recognize  much  of  importance  to  the 
study  of  gout  in  the  uric  acid  deposits  obtained  in  the  viscera 
of  birds  after  ligation  of  the  ureters  (by  Ebstein)  or  after 
exclusive  meat  diet  (by  Kionka).  His  has  been  experi- 
mentally able  to  produce  tophi  by  local  injections  of  rela- 
tively insoluble  sodium  monourate  in  dogs  with  coincident 
administration  of  alcohol.  These  coincide  in  detail  with 
spontaneous  gouty  nodules,  and  confirm  the  view  {vide  sup.) 
that  uric  acid  deposits  may  act  as  local  irritants  and  cause 
the  surrounding  tissue  to  become  the  seat  of  an  inflammatory 
infiltration,  and  produce  a  capsule  from  the  granulation  tis- 
sue thus  occasioned.  Spontaneous  formation  of  gouty 
nodules  (as  by  flooding  the  circulation  with  urates)  has  up 
to  the  present  time  not  been  successfully  induced;  and  this 
is  the  real  object  to  be  attained. 

Among  the  different  factors  which  favor  the  development 
of  gout,  as  is  well  known,  alcoholism,  chronic  plumbism,  and 
long  continued  and  excessive  ingestion  of  foods  rich  in  purin 
bodies  are  the  most  prominent. 

Alcoholism. — The  belief  in  a  close  causal  relation  between 
chronic  alcoholism  and  gout  has  been  fully  confirmed  by  thou- 
sands of  examples,  from  the  days  when  the  lusty  Herr  von 


186  PATHOLOGY  OF  PURIN  METABOLISM 

Rodenstein  after  liquidation  of  his  villages  "had  the  gout  in 
his  neck  from  too  many  malmseys,"  down  to  the  present 
time.  We  have  no  knowledge  of  how  alcoholism  disturbs  the 
purin  metabolism.  According  to  Beebe 32  it  is  the  exogenous 
fraction  of  the  purins,  according  to  London 33  the  endogenous 
as  well,  which  bears  the  brunt.  The  latter  believes  that  de- 
struction of  cellular  nucleins  is  heightened  by  the  toxic  effect 
of  the  alcohol.  L.  Pollak,34  in  metabolism  experiments  in 
the  clinic  of  Friedrich  v.  Müller,  observed  a  retention  and 
retarded  elimination  of  uric  acid  in  alcoholics,  such  as  we 
customarily  regard  as  characteristic  of  the  uric  acid  meta- 
bolism of  the  gouty ;  which  serves  to  indicate  the  close  rela- 
tionship existing  between  alcoholism  and  gout.  Why  the 
excretion  is  retarded,  however,  is  as  much  a  puzzle  in  the 
one  case  as  in  the  other.  If,  as  we  have  done  before,  we 
speak  of  an  "increased  retention  effort  of  the  tissues,"  we 
are  practically  throwing  aside  the  humoral  gout  theories. 
There  is,  however,  no  occasion  to  pretend  either  to  ourselves 
or  to  others  that  this  is  the  same  thing  as  a  real  explanation. 
Chronic  Plumbism. — In  cases  of  chronic  lead  poisoning 
Schittenhelm  and  Brugsch  35  found  the  endogenous  uric  acid 
reduced  markedly ;  while  Preti 36  found  the  absolute  quantity 
of  excreted  purin-base  nitrogen  above  normal  in  three  cases 
of  chronic  plumbism.  In  rabbits  in  Julius  Pohl  's  laboratory37 
with  chronic  lead  poisoning  there  was  invariably  met  an  in- 
crease in  the  nitrogen  fraction  representing  the  purin  group, 
this  often  advancing  in  a  striking  manner  on  increasing  the 
intoxication.    However,  the  uric  acid  manifested  no  such 

82  S.  P.  Beebe  (Yale  Univ.,  New  Haven),  Amer.  Jour,  of  Physiol.,  12,  13, 
1904. 

33  A.  Landau,  Deutsch.  Arch.  f.  klin.  Med.,  95,  280,  1909 ;  cf.  also  Jahresber. 
f.  Tierchem.,  38,  639,  1908. 

34  L.  Pollak  (F.  v.  Müller's  Clinic,  Munich),  Deutsch.  Arch.  f.  klin.  Med.,  88, 
224,  1906. 

35  A.  Schittenhelm  and  Th.  Brugsch,  Zeitschr.  f.  exper.  Pathol.,  k,  494,  1907. 

36  Preti,  Deutsch.  Arch.  f.  klin.  Med.,  95,  411,  1909. 

"Rambousek  (J.  Pohl's  Lab.,  Prague),  Zeitschr.  f.  exper.  Pathol.,  7,  1910, 
S.A. 


EFFECT  OF  MEAT  DIET  187 

relative  proportions.  Here,  too,  therefore,  the  subject  is 
open  to  further  study. 

Influence  of  Excessive  Meat  Diet. — Along  with  alcohol- 
ism and  chronic  lead  poisoning,  excessive  ingestion  of  foods 
rich  in  purin  bodies,  particularly  meat,  plays  an  important 
part  in  the  etiology  of  gout.  Some  evidence  of  this  is  to  be 
observed  in  the  geographical  distribution  of  this  fault  of 
metabolism.  In  Japan,  China,  Arabia  and  the  tropics, 
where  meat  is  but  little  used,  the  affection  is  apparently  rare. 
It  is  not  common  in  southern  Europe ;  in  middle  Europe  it 
occurs  more  frequently,  but  in  the  countries  lying  about  the 
North  Sea  and  the  Baltic  it  is  very  frequently  met,  in  Eng- 
land and  Holland  being  almost  endemic.  Perhaps  the  pref- 
erence which  Austrians  show  for  boiled  beef,  which  is  gener- 
ally disliked  by  the  northerners,  explains  why  gout  is  not 
very  common  in  Austria,  as  the  purin-rich  extractives 
remain  within  the  meat  when  it  is  roasted,  but  are  removed 
through  boiling.  For  this  reason  well-boiled  meat,  provided 
the  broth  is  not  included,  presumably,  may  be  considered  as 
food  poor  in  purins. 

Protracted  Feeding  of  Nucleinic  Acid  to  Dogs. — With 
view  of  determining  the  effect  of  long-continued  inundation 
of  the  mammalian  body  with  purin,  the  author's  pupil, 
Hirokawa 38  has  carefully  studied  under  direction  the  purin 
metabolism  of  a  dog  fed  very  regularly  with  additions  of  nu- 
cleinic acid  for  months.  A  small  dog  regularly  fed  on  mixed 
food  was  given  daily  five  grams  of  sodium  nucleinate  for 
three  months  without  manifesting  any  strikingly  harmful 
result  and  without  any  loss  of  weight.  However,  a  marked 
change  in  the  purin  exchange  was  noted.  Whereas  in  the 
first  part  of  the  experiment  out  of  the  total  purin-  and  allan- 
toin-nitrogen  the  results  showed  98.5  per  cent,  as  allantoin 
and  only  1.5  per  cent,  as  purin  bases  and  uric  acid  together, 

"W.  Hirokawa.  Biochem.  Zeitschr.,  26,  441,  1910;  under  the  direction  of 
0.  v.  Fürth. 


188  PATHOLOGY  OF  PURIN  METABOLISM 

the  uric  acid  proportion  gradually  increased  until  after  ten 
weeks  about  ten  times  as  much  was  being  excreted  as  in  the 
first  week  on  nucleinic  acid  (13  per  cent,  of  the  combined 
purin  nitrogen  and  allantoin  nitrogen) .  Coincident  increase 
of  the  purin  bases  was  not  appreciable.  The  results  show 
that  the  metabolism  of  the  animal  was  influenced  by  long 
continued  flooding  with  the  products  of  nucleinic  acid  cleav- 
age in  such  a  way  that  the  ability  of  the  dog's  economy  to 
oxidize  uric  acid  almost  completely  into  allantoin  was  appar- 
ently impaired,  and  a  larger  fraction  of  the  former  appeared 
unchanged  in  excretion.  However,  there  was  no  change  in 
the  transformation  of  the  purin  bases  into  uric  acid,  only  a 
a  minimal  amount  of  the  former  appearing  unchanged  first 
and  last. 

Radium  Therapy  of  Gout. — Among  the  newer  attempted 
methods  of  cure  of  gout  the  use  of  radium  for  the  moment 
assumes  the  greatest  interest;  and  it  is  undesirable  to 
pass  it  over  without  at  least  brief  consideration.  The  basis 
for  its  employment  was  developed  in  certain  experiments  of 
Gudzent,39  in  the  Clinic  of  W.  His,  upon  the  effect  of  radium 
emanations  upon  the  solubility  of  monosodium  urate.  As 
previously  mentioned  Gudzent  assumed  that  the  monourate 
of  sodium  in  the  blood  may  exist  in  two  forms  capable 
of  intertransformation  by  intramolecular  rearrangements 
(tautomeric  forms),  the  lactam-  and  the  lactim-forms,  the 
former  of  which,  instable  and  the  more  soluble  of  the 
two,  tends  to  change  into  the  relatively  more  insoluble 
and  stable  lactim.  It  is  claimed  that  radium  rays  are  not 
only  capable  of  inhibiting  this  conversion  but  of  causing 
the  relatively  more  insoluble  salt  to  revert  to  the  more 
soluble  form,40  and  of  catabolizing  the  uric  acid  in  turn 

38  F.  Gudzent  (His's  Clinic,  Berlin ),  Med.  Klin.,  1909,  No.  37,  p.  1381; 
Deutsch,  med.  Wochenschr.,  1909,  921;  27th  Intern.  Kongress,  Wiesbaden,  1910, 
p.  539;  Med.  Klin.,  1910,  No.  42;  Therapie  d.  Gegenw.,  1910,  529;  Zeitschr.  f. 
ärztliche  Fortbildung,  8,  198,  1911. 

*°Cf.  H.  Bechhold  and  J.  Ziegler,  Berliner  klin.  Wochenschr.,  1910,  712; 
Biochem.  Zeitschr.,  20,  189,  1909. 


RADIUM  THERAPY  OF  GOUT  189 

into  more  soluble  substances,  finally  into  carbonic  acid  and 
ammonia.  It  is  said  this  solvent  influence  of  the  radium  rays 
is  effective  in  the  living  body  and  that  the  gouty  individual  is 
benefited  by  this  mode  of  treatment,  which  it  is  claimed  will 
destroy  existing  uric  acid  deposits  in  the  tissues  and  reduce 
the  uric  acid  accumulation  in  the  blood.  Yvr.  His  41  regards 
the  beneficial  influence  of  radium  upon  the  manifestations  of 
gout  as  proved,  commending  its  use  especially  by  inhalation 
of  the  rays,  but  also  advising  that  radiumized  water  be 
drunk,  radium  baths  be  employed  and  radium  salts  injected 
in  the  immediate  neighborhood  of  the  affected  parts.  His 
statements  have  had  many  confirmations,  but  have  also  called 
forth  contradiction  in  as  many  instances.  Incidentally,  at 
the  last  Congress  of  Internists  (Wiesbaden,  1912),  the  op- 
posing opinions  were  brought  out  in  sharp  contrast.  Ac- 
ceptance of  a  favorable  influence  of  radium  treatment  upon 
the  symptoms  of  the  malady  aside,  the  procedure  can  with 
difficulty  be  interpreted  either  in  the  sense  of  increasing  the 
solubility  of  the  monourate  of  sodium  or  of  decomposing 
the  uric  acid.  From  exhaustive  experiments  conducted  by 
E.  v.  Knafn-Lenz  and  W.  Wiechowski  in  the  Vienna  Pharma- 
cological Institute,42  no  effect  at  all  from  even  large  amounts 
of  the  rays  were  recognized,  either  in  destruction  or  in 
increasing  the  solubility  of  monosodium  urate.  As  uric  acid 
is  readily  oxidized  by  ozone,  it  might  perhaps  be  supposed 
that  some  such  process  is  involved ;  but  it  has  been  demon- 
strated that  the  quantity  of  ozone  produced  in  the  air  by 
the  radium  preparations  is  incapable  of  producing  any  ap- 
preciable decomposition  of  uric  acid.  It  is  not  clearly  stated 
under  what  precise  conditions  Gudzent's  contrary  results 
were  obtained.  The  above-named  experimenters  state  that 
when  an  impure  alkaline  preparation  of  radium  was  em- 

41  W.  His,  Internisten  Kongress,  1910  u.  1912;  Berliner  klin.  Wochenschr., 
1911,  197. 

UE.  v.  Knaffl-Lenz  and  W.  Wiechowski  (H.  H.  Meyer's  Lab.,  Vienna), 
Zeitschr.  f.  physiol.  Chem.,  77,  303,  1912. 


190  PATHOLOGY  OF  PURIN  METABOLISM 

ployed  decomposition  readily  took  place  and  suggest  that 
the  alkali  given  off  from  the  glass  container  may  also  be  of 
some  import.  "If  there  is  no  direct  influence  of  the  rays 
upon  monourate  of  sodium,"  say  v.  Knaffl-Lenz  and  Wie- 
chowski, ' '  there  may  possibly  be  an  activation  of  a  uric  acid 
oxidase  existing  in  the  human  tissues  in  mere  traces  to 
explain  the  favorable  effect  of  the  emanation  upon  gout. 
.  .  .  Such  an  influence  of  the  rays,  however,  seems  im- 
probable to  us,  because  in  almost  all  experiments  in  human 
metabolism  the  amount  of  uric  acid  excreted  has  been  found 
increased.43  In  trying  to  explain  the  curative  influence  of 
radium  rays  in  gout  there  is  still  left  the  supposition  that 
the  elimination  of  uric  acid  through  the  kidneys  is  made 
easier  by  the  effect  of  the  rays.  Whether  this  is  to  be 
thought  of  as  a  direct  action  on  the  process  of  secretion  of 
the  uric  acid,  or  whether  it  is  an  indirect  one,  as  His  and 
his  pupils  hold,  facilitating  the  excretion  of  the  uric  acid  by 
inhibiting  inflammation  of  the  organs,  is  a  matter  in  which 
further  experimentation  in  appropriate  lines  is  to  be 
desired."  Since,  according  to  Knaffl-Lenz 's  observations 
on  the  effect  of  large  amounts  of  radium  emanations,  there 
may  not  only  be  an  influence  exerted  upon  the  respiratory 
apparatus  but  upon  the  central  nervous  system  as  well, 
caution  is  always  requisite  in  the  radium  treatment  of  gout.44 
Eecent  investigations  in  Neuberg's  laboratory  have  given 
results  in  accord  with  those  of  Knaffl-Lenz  and  Wiechowski, 
showing  that  radium  rays  have  no  influence  upon  the  solubil- 
ity of  sodium  monourate  or  upon  its  decomposition  into 
C02  and  ammonia.45 

43  H.  Mandel  (Radium  in  Biol.,  1,  163,  1911,  cited  in  Centralbl.  f.  d.  ges. 
Biol.,  12,  No.  2879)  found  the  excretion  curve  of  uric  acid  absolutely  unin- 
fluenced in  cases  of  gout  which  manifested  distinct  improvement  from  the  effect 
of  radium  rays. 

44  E.  v.  Knaffl-Lenz  (H.  H.  Meyer's  Lab.),  Wiener  klin.  Wochenschr.,  25, 
No  12. 

45  P.  Lazarus,  29th  Kongr.  f.  innere  Med.,  Wiesbaden,  Apr.  17,  1912; 
J.  Kerb  and  P.  Lazarus  (Chem.  Dept.,  Physiol.  Instit.  of  the  Berlin  Agric.  High 
School),  Biochem.  Zeitschr.,  ^2,  82,  1912. 


MEDICINAL  TREATMENT  OF  GOUT  191 

Medicinal  Treatment  of  Gout. — So  far  as  the  medicinal 
treatment  of  gout 46  is  concerned,  one  must  confess  frankly 
that  there  is  little  satisfactory  to  be  said.  Colchicin,  the 
immemorially  lauded  poison  of  meadow-saffron,  still  has  its 
adherents,  but  no  one  has  ever  been  able  to  explain  its  mode 
of  action.  It  is  said  that  the  much  used  salicylic  acid  and 
its  many  related  substances  increase  uric  acid  elimination ; 
but  whether  its  beneficial  (frequently  questioned)  influence 
on  gout  is  due  to  this  or  simply  to  some  "antirheumatic" 
effect,  is  unknown.  Quinic  acid  (hexahydrotetraoxybenzoic 
acid)  with  its  numerous  derivatives  may,  perhaps,  be  named 
in  the  same  class ;  but  the  hypotheses  upon  which  its  thera- 
peutic use  was  based  were  unfounded.  (It  was  supposed 
that  quinic  acid,  which  is  transformed  in  the  body  into 
benzoic  acid  and  undergoes  a  hippuric  acid  synthesis,  pre- 
vents glycocoll  from  entering  into  synthetic  production  of 
uric  acid ;  but  it  is  now  known  that  synthetic  formation  of 
uric  acid  from  glycocoll  does  not  occur  in  mammalia.) 

It  is  hard  to  say  what  there  may  be  in  the  idea  that  the 
quinolincarboxylic  acids  increase  uric  acid  elimination 47 ; 
the  very  favorable  effects  attributed  to  phenylquinolincar- 
boxylic  acid  (atophan)  have  recently  been  given  consider- 
able prominence.48  Efforts  to  increase  the  solubility  of  uric 
acid  in  the  blood  by  administration  of  piperazin,  substances 
producing  formaldehyde  by  cleavage  like  hexamethylentet- 
ramine  (urotropin),  nucleinic  acids,  urea,  alkalies  and  alka- 
line waters,  have  as  little  justification  in  theory  as  in  practice. 
A  recent  conclusion  goes  so  far  (vide  supra)  as  to  declare 
that  alkalies  are  not  only  useless  in  gout,  but  are  actually 

*°  Literature  upon  the  Therapy  of  Gout:  0.  Minkowski,  Die  Gicht,  pp.  299- 
322,  Vienna,  1903. 

47  A.  Nicolaier  and  M.  Dohrn,  Deutsch.  Arch.  f.  klin.  Med.,  93,  331,  1908. 

48  W.  Weintraud,  Therapie  d.  Gegenwart,  1911,  97;  R.  Feulgen,  Inaug. 
Dissert.,  Kiel,  1912,  Centralbl.  f.  d.  ges.  Biol.,  1912,  No.  2840;  B.  Bauch 
(Weintraud's  Clinic,  Wiesbaden),  Arch.  f.  Verdauungskr.,  11,  Ergänz.  Heft,  186, 
1911;  E.  Frank,  in  collaboration  with  Przedborski  (Minkowski's  Clinic, 
Breslau),  Arch.  f.  exper.  Pathol.,  68,  349. 


192  PATHOLOGY  OF  PURIN  METABOLISM 

harmful,  and  that  it  is  possible  to  obtain  beneficial  results 
from  long  continued  use  of  hydrochloric  acid,  which  is  sup- 
posed to  alter  the  absorption  capacity  of  the  blood  and 
tissues  for  the  uric  acid.49  Altogether,  F.  Umber 50  comes  to 
the  rather  unedifying  conclusion  "that  all  the  medicinal 
methods  introduced  with  view  of  increasing  uric  acid  elimi- 
nation, of  determining  solution  of  the  uratic  deposits  or  of 
limiting  the  formation  of  uric  acid,  are  entirely  worthless. 
To  the  present  time  we  have  not  known  of  any  means  of 
influencing  the  gouty  metabolism,  and  the  good  results  which 
we  are  getting  as  our  knowledge  advances  are  clearly  due  to 
the  matter  of  diet."  Whether  radium  or  atophan  will 
make  any  difference  in  the  force  of  such  a  statement  can 
only  be  awaited  with  patience. 

The  Diet  in  Gout. — The  present  view  of  the  general  sub- 
ject is  somewhat  as  follows  :  The  true  nature  of  gout  is  still 
unknown ;  but  we  at  least  know  that  the  affection  is  in  some 
way  due  to  an  accumulation  of  uric  acid  in  the  blood  and  that 
increase  of  this  accumulation  is  an  unfavorable  feature. 
Therefore,  in  the  dietetic  management  one  may  proceed  on 
the  idea  that  the  ingestion  of  substances  which  form  uric  acid 
are  to  be  limited  as  far  as  possible.  Here  belong  particu- 
larly the  extractives  of  meat,  as  well  as  those  tissues  which 
are  highly  nucleated  and  therefore  contain  considerable 
nucleinic  acid,  like  thymus,  spleen,  liver,  lungs  and  kidneys. 
These  latter  may  be  forbidden  with  propriety,  as  sufficient 
instances  are  known  where  a  gouty  patient  has  suffered  an 
acute  paroxysm  directly  traceable  to  a  meal  of  thymus 
(bries).  Meat  should  be  eaten  only  when  well  boiled,  not 
roasted.  Meat  broths  and  "whole"  soups,  as  well  as  all  use 
of  meat  extract,  are  to  be  prohibited.  In  the  proscription 
list  coffee  and  tea  should  also  be  placed  because  of  the 
methylpurins    they  contain,    together   with  alcohol   in   all 

49  Falkenstein,   Berl.  klin.   Wochenschr.,  1906,  228;   J.  J.  Schmidt,  Mün- 
chener med.  Wochenschr.,  1911,  No.  83,  1764;    consult  also  van  Loghem,  1.  c. 
M  F.  Umber,  Lehrbu.  d.  Ernährung  und  der  Stoffwechselkr.,  p.  333,  1909. 


THE  DIET  IN  GOUT  193 

forms.  While  the  harmful  effects  of  the  latter  upon  gout 
are  not  understood  in  a  theoretical  way,  that  they  are  real  is 
proved  from  a  practical  standpoint.  Finally,  thorough 
flushing  of  the  body  with  water  seems  a  rational  measure. 
These  provisions  form  the  theoretical  fundamentals  of  diet 
in  gout,  as  the  author  understands  them.  For  the  rest  he 
would  refer  to  the  methods  of  practicing  physicians  as  they 
appear  in  numerous  monographs.  It  would  be  impolitic  and 
essentially  wrong  to  simply  ignore  whatever  judicious  objec- 
tive observers  have  found  appropriate  after  decades  of  study 
merely  because  no  theoretical  explanation  therefor  has  been 
found.  It  should  never  be  forgotten  that  the  observations 
of  the  practitioner  may  be  true  and  the  theories  may  be 
false,  and  that  a  judicious  natural  scientist  generally  values 
the  former  more  than  he  does  the  latter.  But  unfortunately 
objective  observation,  especially  in  the  treatment  of  chronic 
internal  affections,  is  endless  and  difficult,  and  for  that  very 
reason  this  has  been  and  will  be  at  all  times  and  among  all 
people  the  favorite  field  for  both  scientific  and  unscientific 
charlatanry. 


13 


CHAPTER  IX 

DIGESTION     OF     CARBOHYDRATES— BLOOD     SUGAR— 
DIASTASIC  FERMENTS 

CARBOHYDRATE  DIGESTION 

Turning  away  for  a  time  from  the  processes  of  meta- 
bolism which  concern  the  proteins  and  nucleins,  our  path 
leads  into  a  new  field  stretching  out  interminably  before 
us — the  field  of  carbohydrate  metabolism.  Even  though 
the  road  be  long,  there  comes  a  feeling  of  relief  as  we  plod 
the  way,  a  feeling  not  unlike  that  the  mountain  climber  ex- 
periences as  he  reaches  the  tree-line  on  a  heated  day  after 
toiling  painfully  up  through  the  high  forest.  Let  the  trail 
before  him  be  grievous  as  it  will,  he  trudges  blithely  along, 
with  freer  vision,  no  longer  shut  in  on  every  side  by  the  dusk 
of  the  thickset  woods.  It  really  is  a  dusk  which  surrounds 
us  in  the  domain  of  protein  metabolism.  How  could  it  be 
otherwise'?  The  chemical  nature  of  the  proteins  is  so  un- 
known, that  in  tracing  their  destinies  in  the  depth  of  the  liv- 
ing body  there  can  be  expected  no  wealth  of  light.  In  taking 
up  the  carbohydrates  we  at  least  are  dealing  with  a  chem- 
ically well-defined  material. 

We  may  at  once  undertake  to  follow  the  carbohydrates  in 
their  transit  through  the  body,  beginning  as  in  case  of  the 
proteins  with  their  fate  in  the  digestive  tract. 

Ptyalin. — As  is  well  known,  the  food  in  man  and  many  of 
the  animals  is  at  once  mixed  in  the  mouth  with  a  diastasic 
(carbohydrate  splitting)  secretion,  the  saliva.  Because  of 
the  fact  that  the  hydrochloric  acid  of  the  stomach  inhibits  the 
glycogenic  action  of  ptyalin  even  when  in  relatively  low 
concentration  and  destroys  the  ferment  entirely  when  in 
higher  concentration  the  opinion  of  many  has  been  and  is 
now  that  ptyalin  action  is  of  comparatively  little  importance 
and  is  quickly  terminated  when  the  food  arrives  in  the  stom- 
ach.    As  a  matter  of  fact,  however,  this  cannot  be  the  case. 

194 


CARBOHYDRATE  DIGESTION  IN  THE  INTESTINE  195 

It  should  be  kept  in  mind  that  when  any  considerable  amount 
of  food  is  ingested  only  that  first  swallowed  comes  into  direct 
contact  with  the  gastric  mucous  membrane.  The  acidity 
need  by  no  means  prevail  in  the  interior  of  the  food  mass, 
and  the  diastasic  action  of  the  saliva  incorporated  in  the 
mass  may  continue  for  some  time  in  the  performance  of  its 
work.1 

Carbohydrate  Digestion  in  the  Stomach. — There  can  be 
no  doubt  of  the  fact  that  there  is  a  carbohydrate  cleavage 
beginning  in  the  stomach  itself,  particularly  as  hydrochloric 
acid  alone,  without  the  aid  of  enzymes,  especially  at  the  in- 
cubator temperature  of  the  stomach  of  the  warm-blooded 
animal,  is  effective  in  this  sense.  According  to  the  investi- 
gations of  the  Ellenberger  school 2  and  others  it  may  be 
accepted  that  many  mammals,  as  the  hog,  produce  a  special 
gastric  diastase.  And  in  the  dog,  the  canine  saliva  being 
devoid  of  diastase,  it  is  said  the  stomach  is  capable  of  form- 
ing a  diastasic  ferment,  one  which  is  active  even  in  strongly 
acid  reaction.  Others,  it  is  true,  have  reached  the  conclusion 
that  the  carbohydrates  generally  undergo  no  appreciable 
alterations  in  the  stomach  of  the  dog,  and  that  a  slight  degree 
of  cleavage  met  there  may  be  explained  by  the  influence  of 
the  hydrochloric  acid  of  the  gastric  juice,  so  that  to  them  the 
assumption  of  an  amylolytic  or  inverting  ferment  seems 
unnecessary.3 

Carbohydrate  Digestion  in  the  Intestine. — However, 
it  may  be  said  that  both  the  cleavage  and  the  resorption  of 
the  carbohydrates  for  the  most  part  reach  their  height 
primarily  in  the  intestine,  where  they  are  subjected  princi- 
pally to  the  powerful  influence  of  the  pancreatic  diastase, 
but  also  to  other  enzymes  as  well  (invertin,  maltase,  lactase). 
Starch   unquestionably   undergoes    a    series    of    catabolic 

1  O.  Cohnheim,  Physiol,  d.  Verd.  u.  Ernährung,  p.  142,  1908. 
2F.  Bengla  and  G.  Haane   (Ellenberger  Lab.),  Pflüger's  Arch.,  106,  267, 
286,  1904;   consult  there  and  also  O.  Cohnheim  (1.  c.)  for  Literature. 
3  London  and  his  associates,  Zeitschr.  f .  physiol.  Chemie.,  56,  1908. 


196  DIGESTION  OF  CARBOHYDRATES 

stages  in  the  intestine.    Whether  this  is  the  proper  time 
to  replace  the  old,  much-discussed  schema 

Starch >Erythro-dextrine >►  Achroodextrine 

>Maltose ^Glucose 

with  a  more  modern  one  need  not  be  further  considered  here. 

Role  of  the  Pancreas  in  the  Production  of  Carbohydrate- 
splitting  Ferments. — As  the  lion's  share  of  the  normal  cleav- 
age of  carbohydrates  in  the  intestines  is  referable,  as  above 
said,  to  the  pancreatic  diastase,  it  is  inconceivable  without 
further  knowledge  how  it  happens  that  in  the  dog,  even  after 
exclusion  of  the  pancreatic  secretion 4  by  ligation  of  the  pan- 
creatic ducts,  as  in  the  experiments  of  Rosenberg,  nine-tenths 
of  the  starchy  materials  may  be  resorbed.  It  is  fundament- 
ally all  the  more  remarkable  because  in  the  dog  we  are  prac- 
tically unable  to  recognize  any  diastasic  influence  in  the 
saliva,  the  bile  and  the  intestinal  juice,  at  least  in  normal  con- 
ditions. If  the  pancreas  be  extirpated  the  resorption  of 
carbohydrate  is  apparently  very  much  disturbed  (although 
Minkowski  and  Abelmann  even  in  this  state  found  their  dogs 
capable  of  resorbing  more  than  a  half  of  the  amylaceous  ma- 
terial fed) .  Whether  we  are  in  fact  constrained  to  ascribe  to 
the  pancreas,  in  addition  to  its  known  function  of  internal 
secretion,  another  specialized  puzzling  role  in  resorption,  as 
Lombroso  belives,5  is  to  the  author's  way  of  thinking  rather 
doubtful.  It  should  be  kept  in  mind  that  total  excision  of  the 
pancreas  is  a  very  severe  interference,  which  "mixes  up," 
so  to  say,  the  whole  economy.  Why  should  it  be  expected  to 
leave  the  carbohydrate  resorption  completely  without  dis- 
turbance f 

Pawlow  has  insisted,  it  may  be  remembered,  upon  his 
doctrine  of  the  adaptation  of  the  digestive  fluids  to  the  par- 
ticular quality  of  food  ingested  according  to  the  require- 
ments.   Weinland 6  and  others  7  have  concluded,  in  special 

*  Cf .  inclusive  Literature :    J.  Munk,  Ergebn.  d.  Physiol.,  1,  308,  1902. 
0  W.  Lombroso  (Turin),  H'ofmeister's  Beitr.,  8,  51,  1906. 


FATE  OF  THE  DISACCHARIDES  197 

reference  to  the  milk-sugar  splitting  function  of  the  pan- 
creas, that  it  is  greatly  increased  or  primarily  induced  by 
milk  diet  in  dogs  and  newly  born  human  beings ;  but  other 
investigations  failed  to  adduce  any  confirmation  of  such 
statements.8 

In  view  of  the  fact  (to  be  discussed  later)  that  the  pan- 
creatic fat-splitting  ferment  is  very  materially  increased  in 
its  effectiveness  by  the  access  of  bile,  it  is  not  without  inter- 
est that  the  bile  also  favorably  influences  the  digestion  of 
starch,  probably  because  the  bile  salts  reduce  the  surface 
tension  of  the  starch  paste.9 

Fate  of  the  Disaccharides. — In  the  resorption  processes 
in  the  intestine  it  is  particularly  important  to  note  that  the 
intestinal  wall  is  strikingly  less  permeable  not  only  for  the 
high-molecular  colloids,  but  also  for  the  disaccharides  than 
for  the  monosaccharides.  It  is  correct  to  say  that  the  bowel- 
wall  apparently  allows  only  those  sugars  to  pass  readily 
which  can  easily  be  used  by  the  tissue  cells.10  The  cells  are 
not  adapted  to  deal  with  the  majority  of  disaccharides,  as 
may  be  recognized  in  the  fact  that  if  cane-sugar  or  lactose  be 
introduced  parenterally,  that  is,  subcutaneously  or  intraven- 
ously, they  are  simply  excreted  without  change.  Although 
this  is  not  true  for  maltose  there  is  a  special  reason,  in  that 
the  blood  contains  a  ferment,  "maltase,"  which  is  capable  of 
splitting  the  parenterally  introduced  sugar,  after  it  has 
entered  the  circulation,  into  glucose.  But  when  we  consider 
the  fact  that  a  man  can  take  up  from  the  intestine  large 
amounts  of  cane  sugar  (three  hundred  grams  and  more) 
without  any  appearing  in  the  urine,  it  is  obvious  that  double 


6E.  Weinland   (Munich),  Zeitschr.  f.  Biol.,  38,  607,  1899;    40,  386,  1900. 

7F.  A.  Bainbridge  (Univ.  College,  London),  Jour,  of  Physiol.,  31,  98,  1905; 
P.  Sioto  (Fano's  Lab.),  Arch  d.  Fisiol.,  4,  116,  1907;  O.  Martinelli  (Bologna), 
Centralbl.  f.  Stoffwechselkr.,  8,  481,  1907. 

*R.  Aders  Plimmer,  Jour,  of  Physiol.,  34,  93,  1906;  35,  20,  1906-07; 
J.  Ibrahim  and  L.  Kaumheimer,  Zeitschr.  f.  physiol.  Chem.,  62,  1909. 

'G.  Buglia  (Bottazzi's  Lab.,  Naples),  Biochem.  Zeitschr.,  25,  239,  1910. 

10  Cf.  E.  H.  Starling,  Handb.  d.  Biochem.,  3",  241,  242,  1909. 


198  DIGESTION  OF  CARBOHYDRATES 

sugars  generally  and  certainly  the  high-molecular  carbohy- 
drates undergo  complete  cleavage  before  they  gain  access  to 
the  blood-stream.11 

This  rule  is  not  invalidated  by  the  fact  that  after  a  diet 
rich  in  carbohydrates,  as  pointed  out  by  v.  Mering,  Otto  and 
others,  dextrin-like  carbohydrates  may  gain  access  in  the 
portal  blood,12  and  that  they  are  recognizable  in  small 
amount  in  urine  normally,  but  to  a  much  greater  extent  in 
diabetes.13 

Dilution  of  a  Sugar  Solution  in  the  Intestine. — According 
to  the  investigations  of  London  carbohydrate  absorption 
in  the  stomach  is  of  little  importance.  If  a  concentrated 
sugar  solution  be  introduced  into  the  small  intestine  sugar 
is  absorbed,  and  at  the  same  time  water  is  given  off  into  the 
intestinal  lumen  until  the  degree  of  sugar  concentration  in 
the  latter  is  reduced  to  about  6  or  8  per  cent.,  after  which  at 
this  dilution  the  resorption  proceeds  rapidly.14  From 
researches  published  from  Röhmann's  laboratory,  the  re- 
sorption of  glucose  from  the  intestine  reaches  its  relative 
maximum  at  a  concentration  corresponding  with  the  osmotic 
pressure  of  the  blood  serum.15 

The  author  would  next  pass  to  the  consideration  of  one  of 
the  problems  relating  to  the  fate  of  carbohydrates  in  the  di- 
gestive tract,  which  is  at  present  of  special  interest  to  him, 
the  problem  of  digestion  of  cellulose. 

Disappearance  of  Coarse  Vegetable  Fibres  from  the 
Digestive  Tract. — In  view  of  the  great  quantities  of  cellulose 
which  vegetarians  ingest  with  the  food  the  question  naturally 
presents  itself  as  to  whether  and  how  this  can  physiologically 
be  made  use  of  in  the  body.    Even  the  early  investigations  of 

11  H.  Bierry,  Biochem.  Zeitschr.,  U,  402,  405,  426,  1912. 

12  J.  Munk,  Ergebn.  d.  Physiol.,  1,  306,  1902. 

13  K.  v.  Alfthan,  Ueber  dextrinartige  Substanzen  im  diabetischen  Harne, 
Helsingfors,  1904. 

14  E.  S.  London  and  W.  W.  Polowzowa,  Zeitschr.  f.  physiol.  Chem.,  56,  513, 
1908;    57,  529,  1908.. 

15 K.  Omi  (Röhmann's  Lab.,  Breslau),  Pflüger's  Arch.,  126,  428,  1909. 


DISAPPEARANCE  OF  VEGETABLE  FIBRES  199 

Haubner,  Henneberg  and  Stohmann,  v.  Hofmeister,  Weiske, 
Knieriem  and  others  left  no  doubt  that  in  vegetarians  a 
portion  of  the  ingested  "coarse  vegetable  fibre"  (a  mixture 
of  celluloses,  hemicelluloses,  pentosans,  lignin  and  similar 
substances  remaining  after  exhausting  vegetable  food  with 
dilute  acids,  caustic  soda,  alcohol  and  ether)  actually  disap- 
pears in  the  intestine.16  We  are  not  dealing  here  with  a 
subtile  matter,  but  on  the  contrary  with  decidedly  gross 
relations  in  that  the  fraction  of  the  ingested  cellulose  which 
vanishes  within  the  digestive  tract  and  fails  to  appear  in  the 
excrement  in  the  herbivorous  domestic  animals  is  estimated 
to  amount  to  from  30  up  to  70  per  cent.  The  degree  to  which 
it  can  be  used  in  the  body  depends  upon  the  character  of  the 
cellulose.  That  of  hay  and  still  more  that  of  tender  young 
plants  is  more  readily  handled  than,  for  example,  is  that  of 
the  bran  of  oat-seed  and  of  barley,  which  is  practically  or 
entirely  indigestible.  Surprisingly,  birds,  even  the  typical 
graminivorous  species,  seem  entirely  unable  to  digest  cel- 
lulose; W.  Biedermann  17  believes  this  is  perhaps  explicable 
by  the  thought  that,  birds  which  live  upon  vegetable  food 
generally  possess  a  powerfully  developed  muscular  stomach, 
by  which  they  are  mechanically  able  to  break  up  into  fine 
bits  the  seeds  they  swallow  without  the  need  of  chemical 
solvents  for  the  cellulose  of  the  hulls.  The  ability  to  digest 
cellulose  is  entirely  absent  from  the  carnivorous  animal, 
especially  the  dog ;  this  may  be  looked  upon  as  settled  by  the 
studies  of  Scheunert  and  others  after  much  controversy.18 
Man  is  apparently  to  be  classed  among  the  vegetarian 
animals  from  his  position  in  relation  to  cellulose.  It  is 
said  that  about  50  per  cent,  of  the  cellulose  and  hemi- 

18  Literature  upon  Cellulose  Digestion :  A  Scheunert,  Handb.  d.  Biochem., 
3",  134-138,  1909;  W.  Biedermann,  Handb.  d.  vergleich.  Physiol.,  2'  1314-1344, 
1911. 

"  W.  Biedermann,  1.  c,  p.  1314. 

13  A.  Scheunert  and  E.  Lötsch,  Berl.  tierärztl.  Wochenschr.,  1909,  No.  47 ; 
Zeitschr.  f.  physiol.  Chem.,  65,  219,  1910;  Biochem.  Zeitschr.,  20,  10,  1910; 
H.  Lohrisch,  Zeitschr.  f.  physiol.  Chem.,  69,  143,  1910;  H.  v.  Hösslin  (Med. 
Clinic,  Halle),  Zeitschr.  f.  Biol.,  54,  395,  1910. 


200  DIGESTION  OF  CARBOHYDRATES 

cellulose  ingested  in  vegetables  and  fruits  is  digested  in  the 
human  canal,  in  habitual  constipation  as  much  as  80  per 
cent.  The  proposal  to  use  it  as  a  substitute  for  the  ordinary, 
readily-resorbed  carbohydrates  in  cases  of  severe  diabetes 
is  related  to  the  assumption  (which,  as  we  will  see  later,  is 
not  yet  satisfactorily  proven)  that  cellulose  undergoes  a 
cleavage  into  sugars  in  full  analogy  to  starch,  but  much 
more  slowly  than  the  latter.19 

Determination  of  Cellulose. — The  differences  of  opinion 
upon  the  availability  of  cellulose  in  the  body  are  partly  to  be 
ascribed  to  theunsatisfactoriness  of  the  methods  used  for  its 
quantitative  estimation.  The  commonly  used  method  of 
Lange  is  based  upon  the  unconfirmed  proposition  that  cel- 
lulose is  not  acted  upon  by  caustic  alkali.  The  practice  of 
Simon  and  Lohrisch,  in  which  the  material  under  examina- 
tion is  heated  with  50  per  cent,  solution  of  caustic  soda  and 
then  decolorized  with  peroxide  of  hydrogen  is  attended  by 
great  losses,  according  to  Scheunert.20  The  latter  author 
recommends  that  the  substance  to  be  examined  be  first  heated 
with  a  highly  concentrated  sodium  hydrate  solution  and  the 
undissolved  residue  washed  well  on  a  hardened  filter,  and 
finally  weighed.  The  ash  of  the  cellulose  thus  obtained  must 
eventually  be  taken  into  consideration. 

Cytases. — How  is  the  digestion  of  cellulose  accomplished? 
One  naturally  at  once  assumes  that  the  organism  of  the  vege- 
tarian can  furnish  ferments  especially  adapted  for  the 
cleavage  of  cellulose  just  as  it  produces  ferments  for  the 
splitting  of  protein,  sugar  and  fat.  And  for  the  lower  forms 
of  animals  an  experimental  foundation  has  been  found  for 
this  assumption.     The  brilliant  researches  of  Biedermann 21 

19  H.  Lohrisch  (Med.  Clinic,  Halle),  Zeitschr.  f.  exper.  Pathol.,  5,  478,  1909; 
F.  Moeller  (Med.  Clinic,  Halle),  Inaug.  Dissert.,  Halle,  1911,  and  Intern.  Beitr. 
z.  Pathol,  u.  Therap.  d.  Ernährungsstörungen,  1,  325,  1910;  F.  Schilling,  Arch, 
f.  Verdauungskr.,  16,  720,  1910;  W.  Biedermann,  Handb.  d.  vergl.  Physiol.,  2', 
1315,  1911. 

"A.  Scheunert,  Handb.  d.  biochem.  Arbeitsmeth.,  3,  277-280,  1910;  W. 
Grimmer  and  A.  Scheunert,  Berlin,  tierärztl.  Wochenschr.,  1910,  No.  7. 

21  W.  Biedermann  and  P.  Moritz,  Pflüger's  Arch.,  73,  219,  1898. 


CYTASES  201 

have  established  the  fact  that  the  hepatic  secretion  of  certain 
molluscs  and  crustaceans  contains  a  very  effective  cellulose- 
solving  ferment,  a  "cytase."  If,  for  instance,  the  liver 
secretion  of  a  Weinberg  snail  is  allowed  to  act  on  a  thin 
section  of  the  starchy  endosperm  of  a  grain  of  wheat  it  will 
be  apparent  that  the  cell  membranes  are  rapidly  dissolved 
even  before  the  enclosed  starch  granules  are  visibly  affected. 
The  energy  with  which  the  gastric  secretion  of  the  snail  dis- 
solves the  thick  and  very  resistive  cell  walls  of  date  seeds, 
ivory  nuts  or  coffee-beans  is  still  more  striking.  It  has  been 
ascertained,  moreover,  that  the  various  celluloses  and  hemi- 
celluloses  are  broken  down  into  the  same  cleavage  products 
(glucose,  mannose,  galactose,  pentoses,  etc.)  by  the  action  of 
cytase,  as  occur  from  the  cleavage  from  boiling  with  mineral 
acids.  There  is,  therefore,  a  real  hydrolytic  cleavage  in 
operation.  The  statements  of  Biedermann  have  been  fully 
confirmed  by  a  series  of  control  tests,22  especially  by  French 
authors.23 

The  expectation  that  an  analogous  ferment  might  be  found 
in  the  intestine  of  vegetable  eating  animals  has  not  been 
realized.  The  mammalian  intestinal  contents,  carefully 
sterilized  by  being  passed  through  a  Berkefeld  or  similar 
filter,  has  always  been  found  inactive  for  cellulose.24  If  the 
cellulose  be  protected  by  the  addition  of  sugar  which  many 
bacteria,  particularly  anaerobic  forms,  prefer  as  their 
source  of  energy  above  any  other  material,  the  cellulose  does 
not  undergo  cleavage, — a  result  which  would  scarcely  be  ex- 
pected if  we  were  actually  dealing  with  a  hydrolytic  cleavage 
from  cytases.23 

22  E.  Müller,  Pflüger's  Arch.,  83,  619,  1901. 

25  H.  Bierry,  J.  Giaja,  M.  Pacaut,  G.  Seillere  and  others  in  C.  R.  Soc.  de 
Biol.;  H.  Bierry  and  J.  Giaja  (Sorbonne,  Paris),  Biochem,  Zeitschr.,  Jf0,  370, 
1912. 

24  A.  Scheunert,  Zeitschr.  f.  physiol.  Chem.,  48,  9,  1906;  and  the  experi- 
ments of  Ellenherger,  V.  Hofmeister,  Holdefleiss  and  H.  T.  Brown,  cited  by 
Scheunert  in  Handb.  d.  Biochem.,  3"  135,  1909. 

25 H.  v.  Hössiin  and  E.  J.  Lesser  (Physiol.  Inst,  and  Med.  Clinic,  Halle), 
Zeitschr.  f.  Biol.,  64,  47,  1910. 


202  DIGESTION  OF  CARBOHYDRATES 

Part  Taken  in  Digestion  by  Enzymes  Contained  in  the 
Food. — A  number  of  years  ago  Ellenberger 26  showed  that 
enzymes  contained  in  vegetable  food  itself  (especially  those 
capable  of  reducing  sugars  and  proteolytic  enzymes)  may 
become  active  when  the  food  is  in  course  of  digestion,  and 
may  aid  the  digestive  juices  contributed  by  the  animal  body. 
It  was  thought  this  was  especially  true  of  the  cytases  of  the 
food,27  although  apparently  this  has  proved  incorrect.  The 
fact  that  in  autolysis  of  wheat  seeds  no  diminution  is  mani- 
fest in  the  cellulose  may  be  taken  to  indicate,  as  Scheunert 
believes,28  that  these  vegetable  cytases  are  of  no  practical 
importance  in  the  digestion  of  cellulose. 

Importance  of  Symbiotic  Microorganisms. — There  is 
nothing  left,  therefore,  but  to  accept  the  view  that  the 
digestion  of  cellulose  is  effected  by  the  microorganisms  of 
the  digestive  tract.  Eeference  has  previously  been  made 
(Vol.  I  of  this  series,  p.  40,  Chemistry  of  the  Tissues)  to 
the  biological  importance  of  the  enormous  quantities  of 
minute  organisms  inhabiting  the  intestine.  "It  is  of  the 
greatest  interest,  and,  in  my  own  opinion,  scarcely  sufficiently 
emphasized,"  says  W.  Biedermann,29  "that  we  are  here 
dealing  with  a  typical  instance  of  symbiosis,  ir  which  foreign 
microorganisms,  originating  from  the  external  world,  by  their 
vital  processes  not  only  facilitate  and  promote  the  thorough 
utilization  of  ingested  foodstuffs,  but  actually  are  more 
capable  of  effecting  this  result  than  any  other  agents." 

Marsh-gas  Fermentation. — What  do  we  actually  know  of 
the  mechanism  of  this  process  of  utilization?  In  the  first 
place  marsh-gas  fermentation  (cleared  up  especially  by  the 
studies  of  Popoff,  Zuntz,  Hoppe-Seyler,  Tappeiner  and 
Omeliansky)  should  be  mentioned,  a  process  which  the  cellu- 

26  W.  Ellenberger,  Skandin.  Arch.  f.  Physiol.,  18,  306,  1906;  and  earlier 
works. 

"P.  Bergmann  (I.  Bang's  Lab.,  Lund),  Skandin.  Arch.  f.  Physiol.,  18, 
119,  1906. 

28  A.  Scheunert  and  W.  Grimmer,  Zeitschr.  f.  physiol.  Chem.,  48,  27,  1906. 

29  W.  Biedermann,  Handb.  d.  vergl.  Physiol.,  %'  1330,  1911. 


FOOD  VALUE  OF  CELLULOSE  203 

lose  undergoes  in  the  intestine  and  in  which  it  is  broken  down 
into  CH4,  C02  and  volatile  fatty  acids  (acetic  acid,  isobutyric 
acid,  valerianic  acid).  Hitherto  marsh-gas  fermentation  of 
cellulose  has  been  usually  regarded  as  about  equalled  by  its 
hydrogen  fermentation.  From  recent  investigations,  ema- 
nating from  the  laboratory  of  N.  Zuntz 39  (in  which  the  gases 
of  fermentation  were  obtained  directly  by  puncture  from  the 
digestive  apparatus  of  a  goat,  in  which  the  paunch  was 
sutured  into  a  wound  of  the  abdominal  wall)  it  is  apparent, 
however,  that  the  hydrogen  of  the  total  fermentation  gases 
never  amounts  to  more  than  10  per  cent,  of  the  methane 
found  with  it.  Under  normal  circumstances  it  would  appear 
that  the  CH4  fermentation  preponderates  to  a  marked  de- 
gree, at  least  as  long  as  the  reaction  of  the  fermenting  mix- 
ture is  acid.  A  simple  chemical  formulation  of  this  fermen- 
tation process  is  at  the  present  out  of  the  range  of  possibility. 
The  part  of  the  tract  in  which  food  rich  in  cellulose  is  prin- 
cipally broken  up  is  in  ruminants  in  the  proventricle 
(paunch) ;  in  other  herbivora  with  single-chambered  stom- 
ach, as  the  horse  and  rabbit,  an  analogous  role  is  to  be  as- 
signed probably  to  the  highly  developed  caecum  in  handling 
cellulose.31  In  man  the  colon  seems  to  be  the  part  concerned 
in  cellulose  digestion.32 

Food  Value  of  Cellulose. — This  brings  us  to  the  main 
point  at  issue — has  cellulose  or  its  fermentation  products  a 
real  value  as  a  nutrient? 33  A  number  of  physiologists 
especially  interested  in  metabolism  have  absolutely  denied 
this  view,  as  Weiske,  who  experimented  upon  a  sheep,  and 
E.  Wolff,  who  worked  on  a  horse ;  while  others,  as  Knieriem, 
Kellner,34  and  recently  Ellenberger  and  Scheunert,  take  the 

30  J.  Markoff  (N.  Zuutz's  Lab.,  Berlin),  Biochem.  Zeitschr.,  3>f,  211,  1911. 

aN.  Zuntz,  Verh.  d.  Berlin,  physiol.  Ges.,  March  10,  1905;  Centralbl.  f. 
Physiol.,  19,  581,  1905;  W.  Ustjanzew  (Zuntz'3  Lab.),  Biochem.  Zeitschr.,  //, 
154,  1907. 

32  F.  Schilling,  Arch.  f.  Verdauungskr.,  16,  720,  1910. 

33  Cf.  W.  Biedermann,  Handb.  d.  vergl.  Physiol.,  p.  1336,  1911. 

34  O.  Kellner,  Die  Ernährung  d.  landwirtschaftl.  Nutztiere,  Berlin,  Parey, 
1906. 


204  DIGESTION  OF  CARBOHYDRATES 

position  that  cellulose,  especially  if  no  other  more  easily 
utilizable  foods  are  readily  available,  may  be  drawn  on  as  a 
food,  and  that  its  nutritive  value  is  to  be  ascribed  as  equiva- 
lent to  that  of  starch  under  proper  circumstances.35 

How  are  we  to  interpret  the  situation?  Apart  from  the 
fact  that  cellulose  fermentation  extracorporeal^  (by  in- 
oculating a  suspension  of  cellulose  in  meat  extract  with  a 
bit  of  intestinal  contents)  proceeds  only  very  slowly,  while 
in  the  animal  body  large  amounts  of  cellulose  disappear  rela- 
tively quickly,  in  its  fermentation  there  arise  products  (like 
methane,  acetic  and  butyric  acids)  which  either  cannot  be 
handled  at  all  or  only  with  considerable  difficulty  by  the 
economy.36  Here  is  an  open  break  in  our  knowledge.  In 
case  cellulose  really  has  an  important  value  as  a  food  (al- 
though this  does  not  seem  so  thoroughly  determined  as  to 
make  further  investigation  undesirable)  there  must  be  hid- 
den back  of  the  method  of  its  utilization  some  process  of 
which  we  are  entirely  in  the  dark. 

Certain  recent  investigations  by  Pringsheim 37  are  prob- 
ably of  importance  in  this  connection.  If  the  full  fermenta- 
tive power  by  cellulose-splitting  microorganisms,  which  nor- 
mally produce  only  methane,  hydrogen,  carbonic  acid,  lactic 
acid  and  the  lower  fatty  acids,  be  inhibited  by  means  of  anti- 
septics, or  (in  case  of  thermophilic  microorganisms)  by  re- 
duction of  temperature,  one  may  without  difficulty  find  in 
the  cultures  in  the  course  of  a  few  days  glucose  and  cel- 
lobiose  (a  disaccharid).  Then,  too,  it  must  be  remembered 
that  lactic  acid  is  also  readily  oxydized  by  the  body  and  may 
be  utilized  by  it. 

Importance  of  Infusoria  in  Cellulose  Digestion. — Per- 
haps, too,  the  very  reasonable  hypothesis   suggested  by 

25  W.  Ellenberger  and  A.  Scheunert,  Lehrb.  d.  vergl.  Physiol,  d.  Haus- 
säugetiere, p.  354,  Berlin,  Parey,  1910. 

a6  Cf .  S.  Fränkel,  Dynamische  Biochem.,  p.  37,  et  seq.,  1911. 

"  H.  Pringsheim  (Chem.  Instit.,  Berlin),  Zeitschr.  f.  physiol.  Chem.,  78, 
266,  1912. 


ESTIMATING  SUGAR  IN  BLOOD  205 

Eberlein  may  afford  some  aid  in  solving  the  puzzle.  In 
the  digestive  tract  of  vegetarian  animals,  as  in  the  proven- 
tricle  of  ruminants,  besides  bacteria  there  are  always  great 
numbers  of  infusoria  of  different  kinds  which  have  been 
introduced  with  the  hay  and  grasses,  which  increase  there 
tremendously  and  may  possibly  be  of  importance  in  the  nor- 
mal process  of  cellulose  digestion.  We  cannot  overlook  the 
possibility  that  these  microorganisms  may  relieve  herbiv- 
orous animals  of  part  of  the  labor  of  digestion  by  trans- 
forming the  cellulose  into  sugar  by  means  of  cytases  for  their 
own  needs  and  utilizing  it  for  building  up  their  own  corporeal 
structure;  then  later  on  when  they  die  and  are  in  turn 
digested,  the  material  they  have  assimilated  may  indirectly 
come  to  be  of  use  to  the  host  animal.  The  proof  of  this 
suggestion  is  somewhat  difficult  because  thus  far  the 
parasites  of  the  stomach  of  ruminants  have  apparently  never 
been  artificially  cultivated,  although  this  should  not  be  very 
difficult  of  accomplishment.38 

BLOOD  SUGAR 

In  continuation  of  the  study  of  the  passage  of  the  carbo- 
hydrates through  the  living  organism  the  next  question  to 
be  considered  is  that  of  the  form  in  which  the  sugar,  when 
resorbed  from  the  intestine,  circulates  in  the  blood. 

Teclmic  of  Estimating  the  Sugar  in  the  Blood. — Prog- 
ress in  the  problem  of  blood  sugar  depends  upon  our  ability 
to  recover  the  minute  amounts  of  the  sugar  unchanged  from 
the  great  quantities  of  albumenoid  blood  colloids  in  which  it 
may  be  said  to  be  buried.  The  technic  of  analysis  of 
haßmic  sugar 39  is  therefore  closely  connected  with  processes 
of  removal  of  albumin.  An  important  and  very  welcome 
improvement  in  this  connection  is  the  method  proposed  by 

38  R.  Eberlein,  Zeitschr.  f.  wissensch.  Zoöl.,  49,  233,  1895;  A.  Scheunert, 
Berlin,  tierärztl.  Wochenschr..  1909,  No.  45;  E.  Liebetanz,  Arch.  f.  Protistenk., 
19,  19,  1910;  W.  Biedermann,  Handb.  d.  vergl.  Physiol.,  2'  pp.  1337-1344,  1911. 

39  Cf.  0.  Schumann  and  C.  Hegler,  Mitt.  a.  d.  Hamburger  Staatskrankenan- 
stalten,  12,  429,  1911 ;    cited  in  Centralbl.  f.  d.  ges.  Biol.,  1911,  No.  1773. 


206  BLOOD  SUGAR 

Michaelis  and  Eona  for  the  removal  of  albumin  by  shaking 
with  a  colloidal  iron  solution,  based  on  the  physical-chemical 
principle  that  two  colloids  of  different  content  will  precipi- 
tate each  other 40 ;  (liquor  ferri  oxydati  dialysati  is  not  in- 
appropriate for  the  purpose).  The  same  principle  is  em- 
ployed by  Möckel  and  Frank 41  in  their  method  of  estimation 
of  sugar  in  the  blood.  Ivar  Bang  and  his  collaborators  42 
remove  the  albumin  with  alcohol,  and  get  rid  of  the  protein 
residue  by  shaking  with  blood  charcoal  in  the  presence  of 
hydrochloric  acid.  The  older  approved  methods  of  remov- 
ing albumin  by  precipitation  by  mercuric  chloride  and 
mercuric  nitrate  or  phosphotungstic  acid  are  in  comparison 
unquestionably  valuable  methods  43 ;  the  author  confesses  he 
could  not  well  dispense  with  them.  When  the  albumin  has 
been  separated,  there  is  no  further  difficulty  in  the  actual  es- 
timation of  the  sugar  in  the  highly  concentrated  fluid  by  some 
one  of  the  reduction  methods,  or  by  polarization  or  fermenta- 
tion in  the  usual  way.  Comparison  of  these  procedures 
show  that  the  old  Fehling's  method  and  the  reduction  meth- 
ods of  Bertrand  and  Kumagawa-Suto  give  practically  the 
same  results,  while  the  hydroxylamine  method  of  Bang  yields 
higher  figures.44  Tachau  has  proposed  a  modification  of 
Knapp  's  method,  consisting  of  adding  excess  of  cyanide  of 
mercury,  separating  the  reduced  mercury,  then  precipitating 
the  mercury  which  remains  in  solution  and  weighing  it.45 
Attempts  have  also  been  made  to  use  various  color  re- 

40  Cf.  P.  Rona  and  L.  Michaelis,  Biochem.  Zeitschr.,  16,  60,  1909. 

41  K.  Möckel  and  E.  Frank  (Wiesbaden),  Zeitschr.  f.  physiol.  Chem.,  65, 
323,  1910;    69,  85,  1910. 

42 1.  Bang,  H.  Lyttkens  and  J.  Sandgren  (Lund) ,  Zeit3chr.  f.  physiol.  Chem., 

65,  497,  1910. 

48  B.  Oppler,  Zeitschr.  f.  physiol.  Chem.,  6k,  393,  1910;  J.  J.  R.  Macleod, 
Jour,  of  Biol.  Chem.,  5,  443,  1909 ;    H.  Bierry  and  Portier,  C.  R.  Soc.  de  Biol., 

66,  577,  1909. 

44  Cf.  I.  Bang,  Biochem.  Zeitschr.,  7,  327,  1908;  D.  Takahaschi,  Biochem. 
Zeitschr.,  37,  30,  1911. 

46  H.  Tachau  ( Schwenkenbecher's  Clinic  and  Embden's  Lab.,  Frankfurt 
a.  M.),  Deutsch.  Arch.  f.  klin.  Med.,  102,  597,  1911. 


EXISTENCE  OF  FREE  SUGAR  IN  BLOOD     207 

actions  peculiar  to  the  carbohydrates  in  colorimetric  estima- 
tion of  the  blood  sugar.  Wacker  has  elaborated  a  method 46 
which  utilizes  a  sensitive  red  color  reaction  given  by 
p-phenylhydrazinsulphonic  acid  with  carbohydrates  in 
presence  of  alkali  (also  with  a  number  of  alcohols  and 
aldehydes.)  By  comparing  the  red  color  with  a  color  scale 
worked  out  from  a  standard  sugar  solution  the  method  is 
said  to  successfully  differentiate  as  small  amounts  as  0.05 
mg.  of  glucose  and  too  requires  only  small  quantities  of 
blood  (about  10  to  15  drops).  In  view  of  certain  inherent 
sources  of  error 47,  the  method  is  of  doubtful  availability. 

Existence  of  Free  Sugar  in  the  Blood. — It  has  been  fre- 
quently asked  whether  the  blood  sugar  is  present  in  the 
blood  free  or  in  colloidal  combination,  as  many  authors  have 
concluded  from  a  variety  of  physiological  and  analytical 
observations  (particularly  from  the  fact  that  sugar,  which 
diffuses  readily,  does  not  normally  pass  through  the  renal 
filter).  Primarily  F.  Schenk,  in  connection  with  his  pioneer 
work  on  the  sugar  of  the  blood,  concluded  because  of  its 
diffusibility  that  the  sugar  is  not  combined  in  any  way  with 
albuminoid  substances,  but  that  it  exists  free  in  the  blood. 
Further  observations  in  the  same  line  have  been  published 
by  Arthus,  and,  too,  by  Asher,48  who  has  been  able  to  prove 
that  diffusion  of  sugar  takes  place  when,  instead  of  water, 
a  like  sample  of  blood,  but  previously  freed  from  sugar  by 
fermentation,  is  used  as  the  outer  fluid.  Finally,  Michaelis 
and  Bona 49  have  shown  in  detail  how  the  sugar  proportions 
in  an  isotonic  salt  solution  may  be  prepared  so  that  in 

46  L.  Wacker  (Würzburg),  Zeitschr.  f.  physiol.  Chem.,  67,  197,  1910; 
L.  Wacker  and  F.  Poly,  Deutsch.  Arch.  f.  klin.  Med.,  100,  567,  1910;  102,  597, 
1911. 

47  Forschbach  and  S'everin  (Minkowski's  Clinic,  Breslau),  Centralbl.  f. 
Stoffwechselkr.,  6,  54,  1911. 

4SL.  Asher  and  R.  Rosenfeld  (Berne),  Biochem.  Zeitschr.,  8,  351-358,  1907; 
consult  therein  Literature;  consult  also  the  objections  of  E.  Pflüger,  Pflüger's 
Arch.,  Ill,  217,  1907. 

4*  L.  Michaelis  and  P.  Rona,  Biochem.  Zeitschr.,  14,  476,  1908,  and  earlier 
contributions. 


208  BLOOD  SUGAR 

dialysis  against  blood,  sugar  will  not  enter  the  blood  or 
diffuse  from  it ;  and  in  the  author 's  opinion  have,  by  this 
"method  of  osmotic  compensation,"  furnished  the  final 
proof  that  the  sugar  exists  free  in  the  blood  or  at  least  in  a 
condition  to  become  free  spontaneously. 

"Sucre  Immediat"  and  "Sucre  Virtuel." — A  second 
question,  however,  presents  itself :  whether  we  may  assume 
that  the  total  amount  of  sugar  in  the  blood  is  in  free  form. 
From  this  point  of  view  the  writer  regards  the  results  of  Le- 
pine  and  Boulud,50  after  a  long  series  of  careful  studies,  as 
apropos.  These  authors  differentiate  in  the  blood  between 
" sucre  immediat"  and  "sucre  virtuel."  The  first  is  de- 
termined by  catching  the  blood  directly  in  an  acid  solution 
of  mercuric  nitrate,  filtering,  pressing  the  blood  cake  dry  and 
determining  the  sugar  in  the  collected  filtrate  after  separa- 
tion of  the  mercury.  The  virtual  sugar,  supposed  to  be 
combined  in  the  blood  as  glucosides,  is  determined  from  the 
increase  of  reduction  power  observed  in  the  blood  after 
keeping  it  for  an  hour  in  the  incubator  with  added  invertin 
or  emulsin  before  estimating  the  sugar.  Apparently, 
however,  the  conversion  of  the  virtual  sugar  into  the  de- 
terminable form  will  take  place  spontaneously  if  it  be  al- 
lowed to  stand  for  a  quarter  of  an  hour;  and  it  has  been 
proposed  to  always  allow  fifteen  minutes  to  elapse  after 
withdrawal  of  the  blood  before  beginning  the  sugar  estima- 
tion.51 It  is  obvious  from  this  that  in  the  above  noted 
diffusion  experiments  the  virtual  sugar  must  in  reality 
appear  as  free  sugar. 

Does  the  Blood  Contain  Other  Carbohydrates  in  Addition 
to  Glucose? — It  may,  therefore,  be  asked  what  significance 
is  to  be  ascribed  to  the  "sucre  virtuel"?  This  is  certainly 
not  a  simple  matter.  The  French  authors,  for  example,  con- 
tinue to  speak  of  "sucre  virtuel"  even  after  heating  the 

00  R.  Lupine  and  Boulud,  Jour,  de  Physiol.,  11,  12,  557,  1909;  13,  178,  1911; 
and  a  number  of  other  contributions  in  C.  R.  and  C.  R.  Soc.  de  Biol. 

11 E.  Frank  (Wiesbaden),  Zeitschr.  f.  physiol.  Chem.,  70,  129,  1910. 


DOES  BLOOD  CONTAIN  OTHER  CARBOHYDRATES  ?  209 

blood  cake  for  twenty-four  hours  with  hydrofluoric  acid. 
They  must  in  this  case  certainly  be  dealing  with  some  glucos- 
amine compounds,  connected  with  the  structural  composition 
of  the  blood  proteids  (and  too,  in  that  of  other  proteins) 
separable  by  hydrolytic  cleavage  from  the  latter;  these  are 
not,  however,  a  part  of  the  true  blood  sugar.52 

Contrary  to  the  statement  that  a  fourth  or  more  of  the 
blood  sugar  which  is  concerned  in  normal  reduction  experi- 
ments is  in  the  form  of  a  non-fermentescible  rest-sugar,53  no 
such  substance  could  be  recognized  by  estimating  the  reduc- 
ing power  of  blood  by  Bertrand's  method  after  fermentation 
either  in  the  blood  or  in  the  serum.54 

It  will  be  readily  realized  that  the  blood  at  times  may  con- 
tain not  inconsiderable  quantities  of  maltose  and  glycogen 
(carbohydrates  which  may  decidedly  increase  the  reducing 
ability  of  the  blood  after  fermentative  cleavage)  .55  It  seems 
doubtful,  however,  whether  these  substances  are  sufficient 
to  fully  explain  the  observations  recorded  in  reference  to 
" virtual  sugar."  In  the  author's  opinion  it  is  more  prob- 
able that  in  this  we  have  to  do  with  phenomena  of  a  physical- 
chemical  nature,  which  we  know  very  well  are  able  to 
markedly  influence  the  conditions  of  solubility  of  sugar. 
Occasion  has  been  taken  in  a  previous  lecture  (v.  Vol.  I  of 
this  series,  p.  170,  Chemistry  of  the  Tissues)  to  call  atten- 
tion to  the  enveloping  phenomena  which  gave  rise  to  the 
mistaken  assumption  of  a  chemical  combination  between 
lecithin  and  glucose  ("jecorin").50  One  may  easily  im- 
agine how  a  part  of  the  sugar  in  the  blood  in  some  such 

"Literature  upon  the  Carbohydrate  Groups  of  Proteins:  L.  Langstein, 
Ergebn.  d.  Physiol.,  1,  91-98,  1902;    Monatshefte  f.  Chem.,  26,  531,  1905. 

63  J.  G.  Otto,  Pflüger's  Arch.,  85,  474,  1885;  N.  Anderson  ( Lund ) ,  Biochem. 
Zeitschr.,  12,  1,  1908. 

M  E.  Frank  and  A.  Brettschneider,  Zeitschr.  f.  physiol.  Chem.,  71,  157,  1911. 

55  Literature:    A.   Magnus-Levy,   Handb.    d.    Biochem.,   V    318-319,    1909; 

E.  Frank    and    Brettschneider,    Zeitschr.    f.    physiol.    Chem.,    76,    226,    1911; 

F.  Spallitta  (Palermo),  Arch.  ital.  de  Biol.,  53,  356.  1910. 

63  Note  the  doubt  expressed  by  P.  Mayer  (Salkowski's  Lab.),  Biochem. 
Zeitschr.,  Jf,  545,  1908,  as  to  the  chemical  individuality  of  jecorin. 

14 


210  BLOOD  SUGAR 

colloidal  investment  might  be  carried  along  in  the  precipita- 
tion of  the  other  blood  colloids  and  thus  escape  estimation; 
while  in  the  sense  of  " virtual  sugar"  it  would  be  recognized 
as  soon  as  freed  from  its  investment  in  the  lecithid  by  any 
suitable  separating  agent.  Whether  this,  in  a  general  way, 
will  satisfactorily  explain  the  activity  of  glucoside-splitting 
ferments,  as  understood  by  Lepine  and  Boulud,  must  be 
left  unanswered.  But  at  any  rate  we  cannot  insist  specifi- 
cally upon  lecithids  as  the  enveloping  factors. 

Sugar  Content  of  the  Red  Blood  Cells. — In  the  last  few 
years  the  question  whether  glucose  is  found  in  the  red  blood 
corpuscles  as  well  as  in  serum  has  been  freely  agitated.  The 
statement  that  these  cells  contain,  not  glucose,  but  only  a  non- 
fermentescible  carbohydrate,  a  polysaccharide,57  is  appar- 
ently contradicted  by  numerous  investigations.  There  is  suf- 
ficient positive  evidence  58  that  the  red  cells  of  fresh  blood  (in 
contrast  with  washed  cells,  which  vary)59  are  permeable  for 
glucose  and  actually  absorb  it  (in  addition,  the  corpuscles, 
as  well  as  the  plasma,  contain  variable  amounts  of  a  complex 
carbohydrate  which  is  converted  into  fermentescible  sugar 
by  hydrolysis).  The  sugar  is  not  always  in  proportionate 
distribution  in  the  plasma  and  cellular  elements ;  sometimes, 
especially  in  hyperglycemias,  very  striking  differences  have 
been  found  in  the  proportionate  amounts  found  within  and 
outside  the  corpuscles,  which  has  been  taken  to  indicate  that 
the  blood  cells  play  an  independent  role  in  sugar  metab- 

67  H.  Lyttkens  and  J.  Sandgren  (Instit.  Med.  Chem.,  Lund),  Biochem. 
Zeitschr.,  26,  382,  1910;  Si,  153,  1911;  36,261,1911;  S.  E.  Edie  and  D.  Spence 
(Liverpool),  Biochem.  Jour.,  2,  103,  1907. 

ML.  Michaelis  and  P.  Rona,  Biochem.  Zeitschr.,  16,  60,  1909;  18,  375,  514, 
1909;  37,  47,  1911;  P.  Bona  and  A.  Döblin,  ibid.,  31,  215,  1911;  R.  Lepine  and 
Boulud,  ibid.,  32,  287,  1911,  and  earlier  contributions;  A.  Hollinger  (Frankfurt 
a.  M.),  ibid.,  17,  1,  1909;  D.  Takahaschi  (Rona's  Lab.),  ibid.,  37,  30,  1911; 
E.  Frank  and  A.  Brettschneider  (Wiesbaden),  Zeitschr.  f.  physiol.  Chem.,  76, 
226,  1911. 

6* Consult  the  studies  of  Hamburger,  Gryns,  Koeppe,  Hedin  and  others: 
Literature  upon  the  Permeability  of  Red  Blood  Cells:  E.  Overton,  Nagel's 
Handb.  der  Physiol.,  2,  828-839,  1907. 


CARBOHYDRATE-SPLITTING  FERMENTS  211 

olism.60  Fundamentally,  the  fact  that  red  blood  cells  con- 
tain sugar  is,  in  the  writer's  opinion,  a  self-evident  one; 
and  he  cannot  suppress  feelings  of  regret  for  the  loss  of 
valuable  time  devoted  by  so  many  noted  investigators  to  this 
matter.  We  have  absolutely  no  reason  to  doubt  that  sugar 
may  penetrate  into  every  living  cell  in  the  system,  to  become, 
as  it  were,  the  ready  cash  for  defraying  the  expenses  of  the 
vital  combustion  processes.  Why  should  the  red  blood  cells 
especially  be  held  different  from  the  rest  ? 

Sugar  in  the  Aqueous  Humor. — In  conclusion  a  new 
method,  devised  by  E.  H.  Kahn,61  should  be  mentioned  for 
rapid  and  simple  reckoning  of  the  proportion  of  blood 
sugar  in  experiment  animals.  The  anterior  chamber  of  the 
eye  is  punctured  with  a  sharp  hypodermic  needle  and  the 
fluid  from  the  chamber  caught  in  a  tube.  It  is  best  to  punc- 
ture one  eye  before  the  experiment,  and  the  other  after  the 
conclusion  of  the  experiment,  and  to  determine  the  differ- 
ence in  the  fluid  from  the  separate  eyes.  If  care  be  taken 
not  to  wound  the  iris  this  interference  is  likely  to  cause  no 
more  than  a  temporary  disturbance  of  vision  in  the  animal, 
as  the  anterior  chamber  is  very  soon  filled  again.  A  hyper- 
glycemia, as  that  brought  on  by  puncture  in  the  fourth 
ventricle  (sugar  puncture),  or  by  adrenin,  or  phloridzin 
becomes  readily  appreciable  by  an  increased  reducing  power 
of  the  fluid. 

CARBOHYDRATE-SPLITTING  FERMENTS 

Another  large  group  of  phenomena,  which  next  demand 
our  attention,  is  that  due  to  the  ferments  which  induce  cleav- 
age of  carbohydrates,  including  the  diastases,  maltases, 
invertases,  lactases,  etc.  It  must  suffice  to  bring  out  here 
only  a  few  points  of  physical  and  pathological  significance, 
and  for  the  rest,  especially  for  all  those  questions  which 

60 R.  Höber  (Kiel),  Biochem.  Zeitschr.,  4-5,  207,  1912. 

"R.  H.  Kahn  (Prague),  Centralbl.  f.  Physiol.,  25,  No.  3,  1911. 


212  CARBOHYDRATE-SPLITTING  FERMENTS 

relate  to  the  kinetics  of  fermentation,  to  make  reference  to 
the  comprehensive  monographs  which  have  appeared.62 

Quantitative  Determination  of  Diastase. — Each  advance 
of  onr  knowledge  of  the  physiological  role  and  importance  of 
the  "carbohydrases,"  especially  of  the  diastases,  presup- 
poses the  possibility  of  their  being  quantitatively  estimated 
with  reasonable  exactness  in  animal  fluids  and  tissues.  In 
a  fluid  this  is  not  particularly  complicated,  aside  from  the 
difficulty,  which  obtains  in  all  fermentation  investigations, 
that  it  is  impossible  to  estimate  the  ferments  directly, 
but  only  possible  to  determine  them  in  terms  of  their  active 
strength.  If  a  fluid  containing  diastase  be  treated  with  an 
excess  of  soluble  starch  or  glycogen  solution,  and  after  a 
time  the  quantity  of  newly  formed  reducing  sugar  calculated, 
an  applicable  measure  of  the  activity  of  the  ferment  is 
obtained.  Because  of  the  difficulties  of  detail  attendant  in 
such  a  method  there  is  need  of  methods  capable  of  affording 
a  quicker  means  of  orientation.  The  method  of  delle  pro- 
duction on  a  starch-paste  plate,  for  example,  has  proved  a 
simple  aid  for  this  purpose  in  the  study  of  diastasic  fer- 
ments.63 In  Pawlow's  Institute,  in  imitation  of  the  well- 
known  Mett  method  of  estimating  pepsin,  the  shortening  of 
starch  cylinders  (made  by  packing  the  starch  in  glass  tubes) 
has  been  employed  for  the  same  purpose.64  A  colorimetric 
method  devised  by  ^Wohlgemuth  has,  however,  proved  to 
be  the  most  useful  of  these  measures;  being  based  upon 
the  determination  of  the  amount  of  ferment  solution  re- 
quired to  so  change  a  known  solution  of  starch,  at  given 
temperature  and  length  of  time,  that  further  bluing  of  the 
solution  will  not  follow  when  iodine  is  added.  The  tints  ap- 
pearing in  serially  arranged  tests  when  iodine  is  added 


62  Literature  upon  Carbohydrate-splitting  Ferments:  F.  Samuely,  Handb. 
d.  Biochem.,  1,  537-546,  1909 ;  C.  Oppenheimer,  Die  Fermente,  3d  ed. ;  II,  66- 
108,  1910;  H.  M.  Vernon,  Ergebn.  d.  Physiol.,  9,  183-193,  1910;  W.  Biedermann, 
Handb.  d.  vergl.  Physiol.,  2'   1397-1402,  1911. 

63  E.  Müller,  Centralbl.  f.  innere  Med.,  1908,  386. 

64  Walter,  cf.  Pawlow,  Arbeit,  der  Verdauungsdrüsen,  Wiesbaden,  1898. 


WIECHOWSKI'S  TISSUE-POWDER  METHOD         213 

(blue,  violet,  red,  yellow),  representing  the  progressive  dis- 
solution of  the  starch,  are  sufficiently  characteristic  to  make 
a  convenient  estimation  possible  from  them.  W.  Schles- 
inger has  also  proposed  a  method  based  on  the  same 
principle.65 

It  becomes  a  much  more  difficult  matter  when  it  is  desir- 
able to  estimate  the  diastases,  not  in  a  fluid,  but  in  a  tissue. 
A  process  may  be  employed  on  the  lines  followed  by  F.  Kisch 
(in  connection  with  an  investigation  made  at  the  author's 
suggestion  upon  the  gradual  loss  of  glycogen  in  the  muscles 
after  death)  by  adding  a  large  excess  of  a  glycogen  solution 
to  a  mushy  mass  of  the  tissue,  and  then  determining  the 
amount  of  newly  formed  sugar  after  lapse  of  a  given  time.66 
An  undesirable  uncertainty  is  inherent  to  methods  of  this 
general  type,  however,  because  there  is  no  guarantee  that 
there  is  not  some  ferment  included  in  tissue  pulp  which  may 
fail  to  come  in  contact  with  the  available  carbohydrate.  The 
author  looks  upon  a  method  devised  by  Wiechowski  for  quan- 
titative ferment  estimation  as  a  very  important  advance 
in  technique,  but  insufficiently  appreciated  as  a  general 
thing,  and  as  having  first  made  possible  a  precise  treatment 
of  a  large  number  of  important  problems  of  the  physiology 
and  pathology  of  metabolism : 

Wiechowski' s  Tissue-Powder  Method. — Wiechowski 's 
method67  is  carried  out  as  follows:  Tissue  obtained  from 
a  freshly  killed  animal,  is  perfused  with  normal  salt  solu- 
tion until  free  from  blood ;  is  then  chopped  into  small  pieces 
and  passed  through  a  fine  sieve.  The  pulp  is  then  spread  out 
in  thin  layers  upon  large  glass  plates  and  dried  by  a  strong 
stream  of  air  from  a  special  ventilator  constructed  in 
properly  adapted  form.     The  tissue  powder  is  next  treated 

05  J.  Wohlgemuth,  Biochem.  Zeitschr.,  9,  1,  1908;  W.  Schlesinger,  Deutsch, 
med.  Wochenschr.,  1908,  593. 

«•F.  Kisch,  Hofmeister's  Beitr.,  8,  210,  1906;  under  direction  of  O.  v. 
Fürth. 

6TW.  Wiechowski,  Hofmeister's  Beitr.,  9,  232,  1907;  Handb.  d.  biochem. 
Arbeitsmethoden,  3',  282,  1909. 


214  CARBOHYDRATE-SPLITTING  FERMENTS 

with  toluol  in  a  special  extraction  apparatus  in  the  cold,  and 
thus  freed  of  fats  and  lipoids.  At  this  stage  the  tissue  con- 
sists of  a  fine  pulverulent  mass  which  includes  proteins  and 
ferments  in  soluble  and  well  preserved  form,  and  affords  an 
excellent  and  well  adapted  supply  of  material  for  quantita- 
tive fermentation  studies.  If  a  weighed  amount  of  the  pow- 
dered tissue  be  rubbed  up  with  physiological  salt  solution 
in  a  mortar,  a  very  fine  emulsion  is  obtained  which  sediments 
only  very  gradually,  and  may  be  subdivided  with  graduated 
pipettes;  and  is  very  well  suited  for  employment  in  com- 
parative study  with  similarly  prepared  powdered  tissue 
from  other  source. 

In  applying  this  method  to  determination  of  the  diastases 
in  tissues,  Starkenstein,68  in  the  laboratory  of  J.  Pohl,  found 
it  essential  to  keep  up  a  continuous  agitation  so  as  to  insure 
adequate  contact  of  the  ferment  and  the  substrate,  lest  the 
tissue  protein,  quickly  coagulating  at  room  temperature, 
take  up  by  mechanical  adsorption  both  starch  and  ferment, 
and  in  this  way  be  sure  to  occasion  too  low  a  result  in  the 
quantity  of  the  latter.  Thereafter  the  actual  estimation 
may  be  conducted  by  the  method  of  Wohlgemuth. 

From  what  has  been  said  we  may  be  satisfied  that  many 
of  the  older  statements  as  to  the  effect  of  various  physio- 
logical and  pathological  factors  upon  the  quantity  of 
diastase  in  the  tissues  have  but  doubtful  value. 

Hepatic  Diastase. — As  for  the  liver,  it  can  be  finally  said 
that  the  constantly  recurring  doubt  as  to  whether  its  vital 
diastasic  activity  is  really  due  to  an  enzyme,  has  been  con- 
clusively settled.69  The  present  attitude  is  to  regard  the 
quantity  of  diastase  in  the  liver  as  subject  to  a  nervous  regu- 
lation ;  and  the  tendency  is  to  relate  starvation  diabetes  of 
the  dog,  as  well  as  the  glycosurias  following  brain  injuries, 
Claude  Bernard's  puncture,  or  administration  of  adrenin, 

68 E.  Starkenstein  (J.  Pohl's  Lab.),  Biochem.  Zeitschr.,  24,  191,  1910. 
69  Consult  Literature  in  F.  Pick,  Hofmeister's  Beitr.,  3,  163,  1902. 


MUSCLE  DIASTASE  215 

phloridzin,  phloretin,  morphin,  strichnin,  etc.,  with  a  sup- 
posed increase  of  hepatic  diastase.  It  is  claimed,  too,  that 
section  of  the  vagus  is  followed  by  marked  increase  in  the 
hepatic  diastase.70  In  view  of  all  such  statements  it  must 
be  regarded  as  very  important  that  Starkenstein,7 1  employ- 
ing a  technical  method  said  to  be  highly  perfected,  has  been 
unable  to  recognize  any  important  increase  of  diastasic 
power  of  the  liver,  either  in  case  of  Bernard's  puncture  or 
after  injections  of  adrenin.  Wohlgemuth,  and,  too  Möckel 
and  Rost  have  also  failed  in  case  of  adrenin  glycosuria  and 
puncture  glycosuria  to  find  any  increase  of  diastase  in  the 
blood  and  tissues.72  It  therefore  seems  highly  improbable 
that  the  exaggerated  output  of  glycogen  from  the  liver,  pro- 
duced by  various  physiological  and  toxic  agencies,  is  really 
an  expression  of  an  activation  of  the  hepatic  diastase. 

Muscle  Diastase. — In  view  of  the  great  physiological  im- 
portance of  muscle  diastase  the  author  assigned  to  F. 
Kisch73  inquiry  into  the  question  whether  muscle  is  able 
to  accommodate  itself  to  the  varying  requirement  of  the 
body  for  mobile  sugar,  perhaps  by  changing  its  diastasic 
power,  possibly  by  forming  fresh  diastase  from  an  inactive 
proferment  whenever  a  need  for  increased  sugar  arises  in 
states  of  hunger  or  fatigue.  No  apparent  difference  was 
found,  however,  in  diastatic  ability  of  the  muscles  of  a  given 
animal  whether  at  rest  or  after  excessive  functional  effort, 
whether  after  full  feeding  or  in  starvation.  We  cannot  but 
assume,  therefore,  that  the  body  has  recourse  to  other  means 
than  the  production  of  diastase  to  mobilize  its  carbohydrate 
supply  at  the  precise  time  when  it  is  needed. 

,0 1.  Bang,  M.  Ljungdahl  and  V.  Böhm,  Hofmeister's  Beitr.,  9,  408,  1907 ; 
10,  1,  312,  1907;    P.  Zegla,  Biochem.  Zeitschr.,  16,  111,  1909. 

"1.  c. 

"J.  Wohlgemuth,  Biochem.  Zeitschr.,  22,  381,  460,  1909;  K.  Möckel  and 
F.  Rost,  Zeitschr.  f.  physiol.  Chem.,  67,  433,  1910. 

73  F.  Kisch,  Hofmeister's  Beitr.,  8,  210,  1906,  under  direction  of  O.  v.  Fürth; 
cf.  therein  Literature  upon  Postmortem  Loss  of  Glycogen  in  Muscles;  cf.  also 
Z.  Gatin-Gruzewska,  Jour,  de  Physiol.,  1907. 


216  CARBOHYDRATE-SPLITTING  FERMENTS 

It  is  impossible  to  say  at  this  time  why  the  cardiac  muscle 
has  so  much  higher  diastasic  ability  than  the  skeletal 
muscles  of  the  same  animal 74 ;  the  marked  access  of  diastasic 
power,  noted  by  Kisch,  in  a  tissue  pulp  transfused  with 
oxygen  in  the  presence  of  blood  may  possibly  have  some 
relation  with  retardation  of  postmortem  lactic  acid 
production. 

Diastases  in  Embryos. — The  observation  of  Alice  Stauber 
in  Exner's  Institute  is  not  without  interest,  showing  that  at 
an  early  stage  of  embryonal  development  diastase  exists  in 
the  parotid  gland  and  in  the  pancreas  (at  a  time  long  before 
any  digestive  activity  of  the  alimentary  apparatus  could 
possibly  be  considered) ;  the  embryonal  thymus,  too,  is 
scarcely  inferior  to  the  pancreas  and  parotid  (organs 
naturally  destined  to  secrete  diastasic  ferments)  in  its 
diastasic  ability.75  The  diastasic  ability  of  muscle  at  an 
early  stage  of  embryonal  life  exceeds  that  of  the  liver,  as 
shown  by  the  careful  quantitative  examinations  of  Lafayette 
Mendel.76 

Origin  of  Diastase. — L.  Haberlandt  has  determined  in 
Zoth's  Institute  that  the  ability  to  form  diastasic  ferment  is 
a  property  of  leucocytes  (particularly  of  the  polymorpho- 
nuclear leucocytes),  the  enzyme  partly  remaining  within 
these  cells,  partly  passing  into  the  surrounding  fluid.  In 
massive  collections  of  leucocytes  in  the  subcutaneous  con- 
nective tissue  (as  induced  by  some  local  irritant)  the 
diastasic  power  of  the  tissue  of  such  a  part  becomes  increased 
and  Haberlandt  believes  the  assumption  justified  that  at 
least  in  part  the  diastatic  ferment  of  the  blood-serum  has  its 
origin  in  the  leucocytes.77 

This  introduces  the  important  subject  of  the  relation  of 

74  Boruttau,  Kisch,  1.  c. 

76A.  Stauber   (S.  Exner's  Lab.,  Vienna),  Pflüger's  Arch.,  UJh  619,  1906. 
76 L.  B.  Mendel,  with  P.  H.  Mitchell  and  Saiki  (Yale  Univ.),  Amer.  Jour,  of 
Physiol.,  20,  81,  1907;    21,  64,  1908. 

77  L.  Haberlandt  (Zoth's  Lab.,  Gratz),  Pflüger's  Arch.,  132,  175,  1910. 


ROLE  OF  THE  PANCREAS  217 

the  tissue  diastase  and  blood  diastase  and  the  source  of  the 
latter. 

Role  of  the  Pancreas  in  the  Production  of  the  Blood  Dias- 
tase.— Observations  showing  that  the  amount  of  diastase  in 
milk  in  the  first  part  of  lactation  may  be  from  one  to  two 
hundred  times  greater  than  that  of  the  blood,7  7a  clearly  indi- 
cate that  the  ferment,  for  the  most  part  at  least,  cannot  in 
such  cases  come  from  the  blood  but  rather  from  the  tissues 
themselves.  Comparative  physiology,  too,  would  suggest 
that  diastases  are  to  be  classed  among  the  enzymes  common 
to  the  general  tisues  and  found  in  all  forms  of  life  from 
the  lowest  to  the  highest.78  For  this  reason  especially  the 
author  has  never  had  any  sympathy  with  ideas  referring 
the  production  of  the  diastase  of  the  blood  and  other  tissues 
solely  to  one  or  more  definite  organs,  as  the  pancreas  and 
salivary  glands.  Yet  it  does  not  in  itself  seem  implausible 
that  diastase  may  be  resorbed  into  the  circulation  from  the 
pancreas  and  eventually  pass  into  the  urine;  but  statistics 
as  to  the  quantity  of  diastase  in  the  blood  of  the  pancreatic 
veins  are  in  general  contradictory  to  this  idea.  However, 
extirpation  of  the  pancreas  seems  sometimes  to  diminish, 
for  a  time  at  least,  the  amount  of  diastase  in  the  blood ;  while 
conversely,  after  ligation  of  the  pancreatic  duct,  the  ferment 
dammed  up  in  the  gland  may  pass  in  decidedly  increased 
amount  into  the  blood  and  thence  into  the  urine.  For  this 
reason  examination  of  the  urine  for  its  diastase  has  been 
recommended  as  a  diagnostic  test  of  the  function  of  the  pan- 
creas.79    Recent  observations  from  Carlson's  laboratory 

"a  J.  Wohlgemuth  and  M.  Strich,  Sitzungsber.  d.  preuss.  Arcad.,  1910,  520. 

78  Cf.  Literature  in  0.  v.  Fürth,  Vergl.  chem.  Physiol,  d.  niederen  Tiere, 
Jena,  1903. 

'•  W.  Schlesinger,  Deutsch,  med.  Wochenschr.,  190S,  593 ;  A.  J.  Carlson 
and  A.  B.  Luckhardt  (Chicago),  Amer.  Jour,  of  Physiol.,  23,  148,  1908; 
J.  Wohlgemuth  and  collaborators,  Biochem.  Zeitschr.,  21,  381,  422,  432,  447,  460, 
1909;  K.  Möckel  and  F.  Rost,  Zeitschr.  f.  physiol.  Chem.,  67,  433,  1910;  J.  J.  R. 
Macleod  and  R.  G.  Pearce  (Cleveland),  Amer.  Jour,  of  Physiol.,  25,  255,  1910; 
G.  Hirata,  Biochem.  Zeitschr.,  27,  23,  1910;  E.  Marino  (M.  Jacoby's  Lab.), 
Deutsch.  Arch.  f.  klin.  Med.,  108,  325,  1911;  J.  v.  Benczur,  Wiener  klin. 
Wochenschr.,  28,  890,  1910. 


218  CARBOHYDRATE-SPLITTING  FERMENTS 

prove  beyond  doubt  that  the  pancreas  cannot  possibly  be  the 
only  source  of  the  blood  diastase.  They  show  that  the  curve 
of  the  blood  diastase,  which  is  deeply  depressed  after  pan- 
creatic extirpation,  rises  again  after  a  few  days,  without, 
however,  fully  regaining  its  normal  level.80  It  is  not  im- 
probable that  the  liver  may  also  give  off  diastasic  ferment 
into  the  blood,81  more  plausible  in  fact  than  the  reverse 
hypothesis  that  the  hepatic  ferment  should  be  derived  from 
the  blood. 

Maltases,  Invertases  and  Gluceses  in  the  Blood-serum. — 
Besides  diastase  maltase  also  is  met  in  the  blood  serum. 
This  has  been  recently  investigated  closely  in  F.  Röhmann's 
laboratory.  In  connection  with  these  studies  brief  inquiry 
was  made  as  to  whether  the  maltase  of  the  blood  serum  is 
capable  in  concentrated  solutions  (as  proved  by  Croft-Hill 
for  yeast  maltase)  of  building  disaccharides  and  poly- 
saccharides from  glucose  molecules;  points  were  noted 
fundamentally  corroborative  of  the  conception  of  such 
synthetic  fermentation.  Following  a  terminology  proposed 
by  Euler  we  would  here  have  to  recognize  the  existence  of 
a  "glucese"  in  the  blood  serum.82 

There  is,  too,  much  of  interest  in  the  recognition  by 
Abderhalden  that  in  the  blood  serum  after  parenteral  intro- 
duction of  a  group  of  carbohydrates  which  do  not  normally 
enter  the  circulation  (as  cane  sugar,  milk  sugar  or  starch) 
ferments  may  be  found  which  are  capable  of  inducing  cleav- 
age of  such  substances.83 

80  H.  Otten  and  T.  C.  Galloway  ( Carlson's  Lab.,  Chicago ) ,  Amer.  Jour,  of 
Physiol.,  26,  347,  1910;  cf.  also  S.  van  de  Erve  (Carlson's  Lab.),  ibid.,  29,  182, 
1911. 

41  A.  Pugliese,  Arch,  di  Farmacol.,  12,  1,  cited  in  Centralbl.  f .  Physiol.,  20, 
827,  1906. 

89 CI.  Kusumoto,  L.  Doxiades  (F.  Röhmann's  Lab.),  Biochem.  Zeitschr., 
U,  217,  1908;  32,  410,  1911;  38,  306,  1912. 

83  E.  Abderhalden,  with  C.  Brahm,  G.  Kapfberger  and  E.  Rathsmann, 
Zeitschr.  f.  physiol.  Chem.,  64,  429,  1910;  69,  23,  1910;  71,  367,  1911.  Litera- 
ture upon  Animal  Invertases:  C.  Oppenheimer,  Die  Fermente,  3d  ed.,  II,  p.  40, 
1910. 


ACTION  OF  DIASTASE  ON  STARCH  219 

Action  of  Diastase  on  Various  Forms  of  Starch. — The 
utilization  of  complex  carbohydrates  by  the  body  is  clearly  a 
very  complicated  process  as  was  believed.  Sigmund  Lang 
confirmed  this  in  his  comparative  studies  upon  the  influence 
of  pancreatic  diastase  upon  starches  from  different  sources, 
showing  that  oats  starch,  which  is  highly  resistive  to  catabol- 
ism  into  products  which  do  not  give  a  color  reaction  with 
iodine,  is  very  readily  converted  into  sugar;  that  potato 
starch,  conversely,  while  very  readily  decomposed  into 
achroödextrin,  is  converted  into  sugar  only  very  slowly. 
This  behavior  of  oats  starch  to  diastase  is  scarcely  con- 
sonant with  the  strikingly  favorable  results  obtained  by  the 
' '  oats  treatment ' '  employed  by  v.  Noorden  for  diabetes.  On 
the  other  hand,  it  is  questionable  whether  it  is  really  proper, 
as  is  usually  done  at  the  present  time,  to  make  the  disappear- 
ance of  the  iodine  reaction  the  basis  of  quantitative  de- 
termination of  the  effect  of  diastase,  and  whether  it  would 
not  be  better,  as  Lang  proposes,  to  estimate  the  effectiveness 
of  diastasic  ferments  from  the  amount  of  end-product, 
glucose,  than  from  such  arbitrary  intermediate  product.  In 
the  end  it  is  undoubtedly  the  end-product  which  concerns  the 
requirements  of  the  body.84  It  is  well  to  recall  here  besides 
that  the  individual  phases  of  starch  cleavage  are  by  no  means 
well  known,  and  that  the  "dual  enzyme  theory"  (strongly 
opposed  by  plant  physiologists)  is  still  a  matter  of  dispute 
(this  theory  assuming  that  diastase  is  not  a  single  ferment 
but  is  composed  of  two  different  enzymes,  maltase  and 
dextrinase).85 

Attempts  to  "isolate"  diastase  have  failed  of  satisfac- 
tory result,  precisely  as  in  the  case  of  other  ferments.86  In 
contrast,  the  physical-chemical  behavior  of  diastase  is  ap- 
parently an  inexhaustible  mine  of  notable  observations. 

M  S.  Lang  (F.  Kraus's  Med.  Clinic,  Berlin),  Zeitschr.  f.  exper.  Pathol,  und 
Ther.,  8,  1910,  s.  a. 

85  Literature :   C.  Oppenheimer,  Die  Fermente,  3d  ed.,  Ill,  pp.  84-86,  1910. 

86  S.  Fränkel  and  M.  Hamburg,  Hofmeister's  Beitr.,  8,  3S9,  1906;  E.  Pribram 
(Fränkel's  Lab.) ,  Biochem.  Zeitschr.,  U,  293,  1912. 


220  CARBOHYDRATE-SPLITTING  FERMENTS 

Thus  it  has  been  noticed  that  diastases  are  at  least  partly 
inactivated  by  prolonged  dialysis  and  may  be  reactivated  by 
the  addition  of  certain  salts  87 ;  that  the  blood  serum  contains 
a  substance  which  is  resistive  to  boiling  and  is  soluble  in 
alcohol,  which  apparently  augments  the  diastases  88 ;  that 
hydrolysis  of  starch  is  strengthened  by  alternating  currents 
of  low  intensity 89 ;  that  there  is  a  hydrolyzing  influence  in 
the  ultra-violet  rays  of  a  mercury  quartz  lamp,90  etc.  For 
the  most  part,  however,  these  matters  fall  within  the  sphere 
of  physical-chemistry;  and  are  beyond  the  limitations  set 
for  these  lectures. 

87  H.  Bierry  and  J.  Giaja,  C.  R.  Soc.  de  Biol.,  60,  749,  1131,  1906;  62,  432, 
1907;  C.  R.,  143,  300,  1906;  L.  Preti,  Biochem.  Zeitsclir.,  //,  1,  1909;  I.  Bang, 
ibid.,  32,  417,  1911. 

88  J.  Wohlgemuth,  Biochem.  Zeitschr.,  33,  303,  1911. 

89 A.  Lebedew  (Moscow),  Biochem.  Zeitschr.,  9,  392,  1908. 
80  H.  Bierry,  V.  Henri  and  A.  Ranc,  Jour,  de  Physiol.,  13,   700,   1911; 
L.  Massed,  C.  R.,  152,  902.  1911 ;   J.  Giaja,  C.  R.  Soc.  de  Biol.,  12,  2,  1912. 


CHAPTER  X 

GLYCOGEN.      FORMATION   OF   SUGAR    FROM   PROTEIN 

AND  FAT 

GLYCOGEN 

In  the  present  lecture  we  have  first  to  take  up  the  subject 
of  glycogen.  This  is  a  reserve  form  of  carbohydrate  which 
plays  very  much  the  same  role  in  animal  metabolism  as 
starch  does  in  plant  life,  and  its  lot  stands  in  very  close  con- 
nection with  the  general  questions  of  carbohydrate  metab- 
olism. One  need  not  wonder,  therefore,  that  the  literature 
upon  the  subject  is  a  very  extensive  one,  so  bulky  in  fact 
that  there  would  be  occasion  for  doubt  whether  it  would  be 
possible  to  properly  systematize  even  its  principal  features, 
were  it  not  for  the  fact  that  two  scientists,  Edward  Pflüger 
and  Max  Cremer,  had  devoted  themselves  to  the  laudable 
task  of  sifting  and  arranging  it.  Thanks  to  their  work  it  is 
no  longer  a  matter  of  great  difficulty  to  review  with  a  reason- 
able degree  of  clarity  the  problems  which  glycogen  research 
faces  for  the  immediate  future.1 

Quantitative  Determination  of  Glycogen. — Our  ability  to 
estimate  with  precision  the  glycogen  supply  accumulated  in 
the  tissues  has  been  of  the  greatest  importance  for  research 
in  carbohydrate  metabolism.  In  some  of  the  later  years  of  his 
activity  Edward  Pflüger  performed  a  service  of  lasting  value 
by  devoting  his  attention  to  the  problem  of  quantitative  es- 
timation of  glycogen,  applying  to  it  his  phenomenal  ability 
and  thorough  critical  acumen.  It  will  not  be  easy  for  pos- 
terity to  replace  Pflüger 's  method  with  a  better.  This 
process  consists  in  dissolving  the  tissues  in  a  highly  con- 
centrated solution  of  caustic  potash,  precipitating  the  glyco- 

1  Literature  upon  the  Physiology  of  Glycogen:  E.  Pflüger,  Das  Glycogen, 
2d  ed.,  Bonn,  1905,  and  Pflüger's  Arch.,  96,  1-398,  1903;  M.  Cremer,  Ergebn.  d. 
Physiol.,  1',  803-909,  1902;  E.  Pflüger,  Pflüger's  Arch.,  96,  55-127,  1903. 

221 


222  GLYCOGEN 

gen  from  solution  by  alcohol,  converting  it  by  hydrolysis  into 
sugar  and  determining  the  latter  directly.2 

Chemistry  of  Glycogen. — The  chemical  study  of  glycogen 
is  almost  stationary.  It  is  true,  Madame  Gatin-Gruzewska  3 
seems  to  have  succeeded  once  in  Pflüger  's  laboratory  in  ob- 
taining it  in  the  form  of  minute  prismatic  crystals;  the 
method  pursued  consisting  in  adding  alcohol  to  a  weak 
solution  of  glycogen  until  turbidity  began  to  appear,  dissolv- 
ing the  precipitate  in  water  and  allowing  this  solution  to 
stand  in  the  refrigerator.  Little  further  has  been  heard  of 
the  procedure.  The  molecular  weight  of  glycogen  is  un- 
doubtedly very  great.  Zdenko  Skraup,  in  collaboration 
with  E.  v.  Knaffl-Lenz,  has  attempted  its  determination, 
treating  the  glycogen  with  acetic  acid  anhydride  saturated 
with  hydrochloric  acid.  With  polysaccharides  it  is  possible 
in  this  way  to  obtain  chlor  acetyl  products,  the  chlorine  of 
which  may  then  be  used  in  deduction  of  the  molecular  weight 
of  the  original  substances;  in  case  of  glycogen  the  figure 
obtained  was  about  24000.  Really,  however,  the  molecule  is 
probably  even  larger.4  The  well-known  opalescence  of 
glycogen  solutions  depends  upon  ultramicroscopic  particles 
suspended  in  it,  as  observed  by  Rählmann  and  others,  these 
particles  being  capable  of  uniting  to  form  granules  of  larger 
size,  and  determining  the  physical-chemical  characteristics 
of  the  solutions.5  It  goes  without  saying  that  under  these 
circumstances  it  is  difficult  to  expect  much  from  cryoscopic 
determinations.6 

2  Literature  upon  the  Quantitative  Estimation  of  Glycogen :  E.  Salkowski, 
Biochem.  Zeitschr.,  1,  337,  1903;  K.  Grube,  Handb.  d.  Biochem.,  2,  159-166, 
1910;  cf.  also  W.  Grebe,  Pflüger's  Arch.,  121,  602,  1908;  B.  Schöndorff, 
P.  Junkersdorf  and  G.  Franke,  ibid.,  126,  578,  582,  1909;   121,  277,  1909. 

3Z.  Gatin-Gruzewska,  Pflüger's  Arch.,  102,  569,  1904. 

4Zd.  H.  Skraup,  Monatsh.  f.  Chem.,  26,  1415,  1905;  E.  v.  Knaffl-Lenz 
(Chem.  Instit.,  Gratz),  Zeitschr.  f.  physiol.  Chem.,  46,  293,  1905. 

BCf.  Z.  Gatin-Gruzewska  and  W.  Biltz,  Pflüger's  Arch.,  105,  115,  1904; 
F.  Bottazzi  and  G.  d'Errico  (Naples),  ibid.,  115,  359,  1906. 

"Literature  upon  the  Chemistry  of  Glycogen:  C.  Neuberg  and  B.  Rewald, 
Biochem.  Handlexikon,  2,  255-264,  1911. 


CHEMISTRY  OF  GLYCOGEN  223 

One  can  readily  understand  how  a  colloidal  substance 
like  glycogen,  distributed  as  it  is  in  another  colloidal  sub- 
strate, the  cellular  protoplasm,  often  comes  to  show  an 
atypical  behavior.  Thus  the  microchemical  identification 
of  glycogen  by  iodine-iodide  of  potassium  (as  in  a  frog's 
ovary)  may  be  attended  with  difficulties  even  though 
glycogen  is  abundantly  present ;  but  if  the  combination  be- 
tween glycogen  and  the  tissue  be  released  by  repeated  freez- 
ing and  thawing  of  the  latter,  the  reaction  readily  takes 
place.7  We  are  manifestly  here  dealing  with  a  phenomenon 
of  physical  chemistry ;  as  we  have  no  foundation  at  present 
for  assuming  a  chemical  combination  of  the  glycogen  within 
the  tissue.8  Moreover,  R.  Türkei  (in  opposition  to  the  state- 
ments of  Seegen  and  others)  was  unable  to  convince  himself 
that  liver-extracts,  freed  of  their  glycogen,  fermentescible 
sugar  and  albumen,  contain  any  appreciable  quantities  of  a 
substance  which  may  be  precipitated  by  alcohol  or  which 
will  yield  sugar  by  hydrolytic  cleavage.9 

That  the  tremendous  application  of  work  devoted  during 
the  past  decades  to  experimental  investigation  of  the  physi- 
ology of  glycogen,  the  details  of  which  obviously  cannot  here 
be  discussed,  has  not  been  without  result,  may  be  realized 
when  it  is  stated  that  we  are  able  even  now  to  indicate  con- 
cisely the  conditions  under  which  the  body  draws  upon  its 
glycogen  supply.10  (We  have  more  definite  information 
about  this  phase  of  the  subject  than  in  regard  to  the  manu- 
facture of  glycogen  in  the  body,  a  feature  undoubtedly 
related  with  the  important  and  very  imperfectly  understood 
questions  of  formation  of  sugar  from  proteins  and  fats.) 

TM.  Bleibtreu,  K.  Kato,  Pflüger'a  Arch.,  127,  118,  125,  1909. 

*H.  Loeschke  (Pfliiger's  Lab.),  Pfluger's  Arch.,  102,  592,  1904. 

»R.  Türkei,  Hofmeister's  Beitr.,  9,  89,  1906;  cf.  therein  Literature. 

10  Literature  upon  Physiological  and  Pathological  Catabolism  of  Glycogen 
in  the  Body:  0.  v.  Fürth,  Ergebn.  d.  Physiol.,  2,  584-589,  1902;  R.  Tigerstedt, 
Nagel's  Handb.  d.  Physiol.,  1,  495-502,  1905 ;  E.  Weinland,  ibid.,  2,  430,  1907 ; 
A.  Magnus-Levy,  Handb.  d.  Biochem.,  4'  311-316,  1909;  J.  Wohlgemuth,  ibid., 
8',  160-161,  168-174,  1910. 


224  GLYCOGEN 

Relation  Between  the  Consumption  of  Sugar  by  the 
Muscles  and  the  Disappearance  of  Glycogen  of  the  Liver. — It 
is  commonly  accepted  that  glycogen  is  one  of  the  generally 
distributed  tissue  constituents.  Its  distribution  in  the  econ- 
omy is,  however,  by  no  means  uniform,  by  far  the  greatest 
proportions  being  accumulated  in  muscle  and  the  liver.  The 
extent  of  its  accretion  in  these  latter  structures  is  illustrated 
by  the  fact  that  in  a  frog's  liver  glycogen  may  actually  con- 
stitute more  than  half  of  the  dried  substance.11  In  view  of 
the  unquestioned  importance  of  sugar  as  a  source  of  mus- 
cular power  it  may  be  appreciated  why  the  living  body 
should  generally  show  a  more  constant  fixation  of  muscle 
glycogen  than  of  liver  glycogen;  and  among  the  different 
muscles  why  the  heart  should  give  up  its  glycogen  least 
readily.  By  long-continued  strychnine  convulsions,  which 
is  one  of  the  most  effective  means  of  inducing  the  body  to 
use  up  its  supply  of  glycogen,  P.  Jensen  ultimately  suc- 
ceeded in  getting  the  frog's  heart  free  of  glycogen  and  show- 
ing that  even  then  it  is  capable  of  continuing  its  activity.  As 
long  as  the  body  has  a  carbohydrate  supply  at  its  disposal, 
however,  the  functionating  muscles  are  sure  to  find  some 
means  and  some  way  to  obtain  it;  but  how  they  actually 
accomplish  this  is,  it  must  be  confessed,  at  present  unknown. 
There  has  been  a  hypothesis  that  in  muscular  contraction  the 
intramuscular  nerve-endings  are  stimulated  and  transmit, 
as  it  were,  telegraphic  information  to  the  great  central  sup- 
ply office  in  the  liver  to  provide  additional  fresh  nutrient 
material;  but  as  a  matter  of  fact  no  one  has  proved  such 
relationship.  It  is  quite  possible  that  nervous  telegraphic 
lines  have  nothing  whatever  to  do  with  notifying  the  liver 
and  other  organs  that  assistance  is  needed  for  the  muscles. 
It  may  very  well  be  that  the  circulating  blood  enacts  this 
role  of  messenger  automatically  when  its  level  of  sugar  is 
lowered.     There  is  no  doubt  that  in  a  general  way  the 

11 M.  Bleibtreu,  Mitt.  a.  d.  Naturwiss.  Vereinigung  für  Neuostpommern 
und  Rügen,  1907,  cited  in  Centralbl.  f.  Physiol.,  22,  448,  1908. 


GLYCOGEN  IMPOVERISHMENT  225 

mobilization  of  sugar  in  the  liver  is  presided  over  by  nervous 
influences,  following  the  evidence  given  by  the  gifted  Claude 
Bernard  when  he  announced  his  "sugar  puncture"  and 
showed  that  injury  of  the  floor  of  the  fourth  ventricle  is 
followed  by  glycosuria.  The  same  thing  has  since  then  been 
noted  after  divers  wounds  in  the  general  field  of  the  nervous 
system;  and  the  present  belief  is  that  the  function  of  the 
liver  in  carbohydrate  metabolism  is  under  the  regulating 
influence  of  a  "sugar  centre"  in  the  medulla  oblongata,  the 
vagus  nerves  carrying  centripetal  impulses  and  the  splanch- 
nics  centrifugal.  According  to  Ernst  Freund  and  H.  Pop- 
per in  the  dog  an  abundant  deposit  of  glycogen  can  be 
obtained  in  the  liver  from  intravenous  injections  of  sugar, 
only  if  all  cerebral  stimulation  is  eliminated,  either  by 
narcosis  or  by  interruption  of  the  centrifugal  nervous 
paths.12 

Production  of  Glycogen  Impoverishment  in  the  Body. — 
Besides  muscular  activity  there  are  a  great  number  of  other 
physiological  and  pathological  factors  known  which  may  pro- 
duce reduction  in  the  body  supply  of  glycogen.  All  forms  of 
inanition  should  be  prominently  named  in  this  connection 
in  which  loss  of  sugar  from  the  economy  as  in  pancreatic, 
phloridzin  or  adrenin  diabetes  may  give  rise  to  such  serious 
exaggeration  as  to  impoverish  the  system  of  its  carbohy- 
drates. Here,  too,  should  be  classed  increased  heat  produc- 
tion, as  seen  in  fever  and,  too,  in  exposure  to  cold;  and, 
finally  the  influence  of  local  hepatic  lesions  (as  from  ligation 
of  the  hepatic  duct  or  from  injection  of  acid  into  the  bile 
duct)  and  of  intoxications  (as  from  phosphorus,  arsenic, 
chloroform,  amyl  nitrite  and  many  others)  should  be  added. 
Among  the  poisons  which  cause  degeneration  of  the  liver 
parenchyma  and  disturb  its  glycogen  function,  according  to 
Asher,13  lymphagogues,  like  peptone,  extract  of  crab-muscle 
and  leech-extract,  are  to  be  included. 

B  E.  Freund  and  H.  Popper,  Biochem.  Zeitschr.,  41,  56,  1912. 
13  L.  Asher  and  Kusmine  (Berne),  Zeitschr.  f.  Biol.,  ^6,  554,  1905. 
15 


226  GLYCOGEN 

There  is  little  occasion,  however,  for  lingering  over  these 
essentially  obvious  features,  which  take  up  a  large  part  of 
the  literature  of  the  subject.  Briefly  stated  there  is  scarcely 
any  form  of  pathological  change  in  the  body  which  may  not, 
at  times,  come  to  involve  the  reserve  supplies  of  carbo- 
hydrate which  have  been  stored  up  when  times  were  good ; 
but  the  author  confesses  he  cannot  bring  very  much  interest 
to  bear  upon  the  details  of  these  processes. 

Attention  should  here  be  called  to  the  fact  that  the  im- 
portance of  the  liver  as  the  place  of  greatest  deposit  of 
glycogen  has  been  much  over-estimated  in  connection  with 
the  normal  course  of  carbohydrate  metabolism.  Dogs  can 
undoubtedly  readily  assimilate  and  consume  large  quantities 
of  carbohydrates,  even  after  the  liver  has  been  excluded 
from  the  portal  circulation,  as  by  the  establishment  of  an 
Eck's  fistula  or  by  transient  compression  of  the  portal  vein 
(by  a  suture  carried  about  the  vein  and  through  the 
abdominal  wall)  14  (Cf.  Vol.  I  of  this  series,  p.  296, 
Chemistry  of  the  Tissues). 

Formation  of  Glycogen  in  the  Perfused  Liver. — Turning 
next  to  the  manner  in  which  the  body  builds  up  its  glycogen  it 
may  be  said  that  conclusive  information  upon  the  formation 
of  glycogen  was  reasonably  to  be  expected  from  perfusion 
experiments,  in  which  substances  believed  capable  of  con- 
tributing the  material  for  its  construction  are  introduced 
into  the  blood  used  in  perfusing  the  living,  excised  liver. 
While  at  first  the  procedure  required  the  determination  of 
the  glycogen  in  a  portion  of  the  liver  before  the  inception 
of  the  experiment  and  thereafter  the  perfusion  of  another 
part  of  the  organ,  Grube15  has  devised  a  method  (based  on 


14  F.  de  Filippi  (Rome),  Zeitsehr.  f.  Biol.,  50.  38,  1908;  F.  Verzär  (Tangl's 
Lab.),  Biochem.  Zeitsehr.,  34,  52,  63,  1911;  E.  Wehrle  (Basel),  ibid.,  34,  233, 
1911;  N.  Burdenko  (Dorpath),  Internat.  Beitr.  z.  Pathol,  u.  Tlier.  d. 
Ernährungsstörungen,  4,  93,  1912. 

15  K.  Grube  (Pflüger's  Lab.),  Pflüger's  Arch.,  107,  483,  1905;  cf.  opp. 
H.  Serege  (Bordeaux) ,  C.  E,.  Sbc.  de  Biol.,  57,  000,  1904. 

18 K.  Grube   ( Haliburton's  Lab.,  London),  Pflüger's  Arch.,  101,  590,  1905. 


FORMATION  OF  GLYCOGEN  227 

the  fact 16  that  glycogen  is  uniformly  distributed  in  the 
hepatic  parenchyma  proper,  and  that  any  slight  analytical 
differences  are  related  with  the  variations  in  amount  of 
connective  tissue  in  the  portions  under  examination),  which 
permits  in  the  turtle  artificial  circulation  to  be  maintained 
for  two  completely  separated  portions  of  the  liver.  J.  de 
Meyer 17  has  since  succeeded  in  applying  an  analogous 
method  to  the  mammalian  liver.  It  is  thus  possible  to  per- 
fuse one  lobe  of  the  liver  with  blood  containing  sugar  and 
a  second  with  blood  free  from  sugar.  We  have  learned 
from  observations  of  this  type,  that  a  marked  new-formation 
of  glycogen  takes  place  in  a  liver  when  perfused  with  blood 
containing  sugar;  and  the  assertion  1S  that  the  liver  is  able 
to  form  glycogen  from  glucose  only  after  the  latter  has  un- 
dergone a  preparatory  polymerization  in  the  course  of  its 
resorption  in  the  bowel  has  been  thoroughly  disproved.19 

We  may  go  a  step  further  and  take  up  the  question  of 
what  must  be  the  constitution  of  a  sugar  to  fit  it  as  material 
for  the  formation  of  glycogen.  Based  upon  an  extensive 
literature,  the  details  of  which  cannot  be  taken  up  here, 
this  question  would  be  answered  somewhat  as  follows  at  the 
present.20 

Formation  of  Glycogen  from  Glucose,  Fructose  and 
Galactose. — Besides  glucose,  which  has  naturally  occupied 
the  central  place  in  the  whole  carbohydrate  problem,  there 
are  two  hexoses  which  are  undoubted  glycogen-formersr 
fructose  and  galactose,  the  stereo-chemical  configurations  of 
which  closely  approach  that  of  glucose.     The  capability  of  a 

17  J.  de  Meyer   ( Solvay  Instit.,  Brussels ) ,  Arch,  intern,  de  Physiol.,  8,  204, 
1909. 

18  A.  C.  Croftan  (Chicago),  Pfliiger's  Arch.,  126,  407,  1909. 

19  E.  Pflüger,  Pflüger's  Arch.,  126,  416,  1909;  K.  Grube  (Pflüger's  Lab.), 
Pflüger's  Arch.,  121,  529,  1909. 

20  Literature  upon  Glycogen  Formation  from  Sugars  and  Related  Sub- 
stances: M.  Cremer,  Ergebn.  d.  Physiol.,  1'  896-901,  1902;  R.  Tigerstedt, 
Nagel's  Handb.  d.  Physiol.,  1,  502-503,  1905;  E.  Weinland,  ibid.,  2,  433-499, 
1907;  J.  Wohlgemuth,  Handb.  d.  Biochem..  8',  160-164,  1910;  A.  Magnus-Levy, 
ibid.,  Jt'  323-326,  352-353,  1909;  H.  Haffmanns,  Inaug.  Diss.,  Univ.  Berne, 
1910,  cited  in  Jahresber.  f.  Tierchem.,  40,  414. 


228  GLYCOGEN 

number  of  other  hexoses,  as  the  mannoses,  sorbose  and  chi- 
tose,  to  form  glycogen  seems,  to  say  the  least,  questionable. 
Glycogen  formation  from  the  first-named  types  of  sugar  was 
proved  even  as  early  as  C.  v.  Voit  and  his  school.  They  are 
by  no  means  equally  capable,  galactose  normally  being  fixed 
in  the  form  of  the  reserve  carbohydrate  with  more  difficulty 
than  are  glucose  and  laevulose.  A  fasting,  healthy  human 
being  can  take  up  as  much  as  100.  to  150.  grams  of  glucose 
from  the  stomach  at  one  time  without  excreting  sugar  in  the 
urine;  the  "limit  of  assimilation"  for  galactose  is  very 
much  lower,  about  30.  to  40.  grams.  Galactose  is  assimilated 
with  especial  difficulty  by  Carnivora ;  canine  urine  showing 
reducing  power  even  when  the  animal  is  merely  kept  on  a 
milk  diet,  as  observed  many  years  ago  by  F.  Hofmeister. 
When  Grube  perfused  the  living  excised  turtle-liver  with 
Ringer's  solution  to  which  was  added  sugar  of  different 
kinds,  he  noted  that  large  amounts  of  glycogen  were  pro- 
duced from  glucose  and  from  fruit  sugar  but  far  less  from 
galactose.  It  is  a  strange  thing  that  galactose  is  better 
assimilated  by  the  human  diabetic,  according  to  F.  v.  Voit, 
than  is  glucose,  the  diabetic  patient  having  lost  the  capacity 
of  utilizing  the  latter.  The  same  is  true  of  laevulose,  as  shown 
by  Minkowski  in  case  of  pancreatic  diabetes  and  by  L. 
Pollak 21  in  case  of  adrenin  diabetes.  From  a  further  in- 
vestigation (in  the  Vienna  Pharmacological  Institute)  22 
it  would  seem  that  in  phosphorus-poisoning  the  liver, 
although  it  has  lost  its  power  of  forming  glycogen  from 
glucose,  is  still  able  to  freely  construct  glycogen  when 
laevulose  is  exhibited.  It  is  impossible  thus  far  to  explain 
this  remarkable  peculiarity.  It  might  be  conjectured  that 
the  glycogens  formed  from  laevulose  or  galactose  are  in  some 
way  different  from  the  form  of  glycogen  from  dextrose; 
that  perhaps  the  glycogen  from  laevulose  would  hydrolyse, 

aL.  Pollak  (Pharmacol.  Instit.,  Vienna),  Arch.  f.  exper.  Pathol.,  61,  149, 
1909. 

22  E.  Neubauer  (Pharmacol.  Instit.,  Vienna),  Arch.  f.  exper.  Pathol.,  61, 
174,  1909. 


DISACCHARIDES  AND  POLYSACCHARIDES  229 

not  into  grape-sugar,  but  into  fruit-sugar.  However,  a  series 
of  special  investigations  conducted  by  Pflüger,23  with  this 
point  in  view  and  using  glycogen  from  animals  after  a  diet 
rich  in  lasvulose,  have  failed  to  give  the  least  foundation  for 
such  assumption.  The  liver  and  the  other  organs  as  well 
must  be  looked  upon  as  capable  of  inverting  the  polarizing 
properties  of  sugars  introduced. 

Behavior  of  Disaccharides  and  Polysaccharides. — The 
facts  concerning  the  disaccharides  are  fairly  well  known. 
Cane-sugar  and  milk-sugar  can  be  completely  assimilated 
only  if  they  enter  the  blood  from  the  intestine,  that  is,  after 
undergoing  full  fermentation  cleavage.  When  introduced 
parenterally  they  pass  for  the  most  part  unchanged  into  the 
urine.  Nor  are  they  found  capable  of  forming  glycogen  when 
directly  perfused  through  the  living,  excised  liver  (vide  sup., 
p.  228).  Maltose,  however,  does  not  follow  the  same  rule, 
as  the  blood  and  tissues  contain  "maltases,"  ferments 
capable  of  splitting  this  disaccharide  when  introduced 
parenterally  into  the  circulation;  for  which  reason  it  is 
readily  assimilable.  (Because  of  the  readiness  with  which 
maltose  undergoes  cleavage  into  dextrose,  Murschhausen's 
statement 24  that  this  sugar  produces  much  less  glycogen 
than  grape-sugar,  fruit-sugar  and  cane-sugar  cannot  well 
be  understood.)  It  is  not  to  be  understood  that  the  normal 
body  has  absolutely  no  power  of  splitting  parenterally  intro- 
duced cane-sugar.  Small  amounts  of  this  carbohydrate 
(one  or  two  grams  per  kilo)  introduced  subcutaneously  or 
intravenously  into  a  dog  or  a  cat  (as  Lafayette  Mendell  has 
recently  discovered)  25  are  not  entirely  excreted  in  the  urine. 
Ernst  Weinland 26  observed  that  when  cane-sugar  was  in- 
jected in  large  amounts  subcutaneously  into  grown  dogs  it 
was  usually  entirely  excreted;  but  when  solutions  of  this 
same  sugar  were  injected  into  young  dogs  in  increasing 

23  E.  Pflüger,  Pfluger's  Arch.,  121,  559,  1908. 

24  Pfluger's  Arch.,  1S9,  255,  1911. 

25  L.  B.  Mendel  and  J.  S.  Kleiner,  Amer.  Jour,  of  Physiol.,  26,  396,  1910. 
30  E.  Weinland,  Zeitschr.  f.  Biol.,  ^7,  279,  1906. 


230  GLYCOGEN 

doses  over  a  longer  period  of  time,  the  serum  would  take  on 
inverting  properties.  This  is  evidently  nothing  more  than 
an  exaggeration  of  a  property  which  is  already  normally 
possessed,  perhaps  in  analogy  to  the  phenomena  noted  in 
the  observations  of  Abderhalden  already  mentioned  (vide 
sup.,  p.  218).  The  same  thing  is  indicated  by  the  studies  of 
Hohlweg  and  Voit,27  who  noted  almost  complete  elimination 
after  subcutaneous  injection  of  twenty  grams  of  cane-sugar 
into  normal  rabbits ;  while  in  animals  with  their  metabolic 
processes  increased  by  overheating  a  loss  of  about  twenty 
per  cent,  was  obtained. 

That  polysaccharides  like  starch  and  inulin,  which  under- 
go cleavage  into  glucose  or  laevulose  in  the  intestine,  con- 
tribute to  glycogen  formation  is  self-explanatory.  As  re- 
sorption of  these  substances  can  take  place  only  after  com- 
plete cleavage  has  occurred,  large  amounts  may  be  ingested 
by  human  beings  without  necessarily  inducing  excessive 
presence  of  sugar  in  the  system  and  without  consequent 
alimentary  glycosuria. 

Other  Substances  of  the  Sugar  Series. — Statements  as  to 
the  glycogen  forming  properties  of  the  pentoses  are  more  or 
less  confusing 28 ;  off-hand  it  must  be  regarded  as  very 
questionable  whether  they  possess  such  properties.  Con- 
version of  the  pentoses  into  glycogen,  as  a  matter  of  fact, 
would  be  possible  only  in  a  very  round-about  way  (decompo- 
sition into  molecular  groups  with  two  or  three  carbon 
atoms). 

It  is  rather  singular  that  glucosamine  cannot  be  classed 
among  the  glycogen  producers  when  one  thinks  how  close  it 
stands  to  grape-sugar  stereochemically  29 ;   the  body  is  evi- 

"H.  Hohlweg  and  F.  Voit  (Giessen),  Zeitschr.  f.  Biol.,  51,  491,  1908. 

28  M.  Cremer,  Salkowski,  Frentzel,  Neuberg  and  Wohlgemuth ;  cf .  critical 
review  of  the  Literature;  M.  Cremer,  Ergebn.  d.  Phyäiol.,  1'  898-899,  1902; 
cf.  also  L.  B.  Stookey  and  A.  H.  Jones,  Proc.  Soc.  Exper.  Biol.,  5,  123;  cited 
in  Jahresber.  f.  Tierchem.,  38,  446,  1908. 

28  Fabian,  S.  Fränkel  and  Offer,  Cathcart,  Bial,  Forschbach,  K.  Meyer, 
Hofmeister's  Beitr.,  9,  134,  1907;  F.  Rogozinski,  C.  R.,  153,  211,  1911. 


FORMALDEHYDE  231 

dently  unable  to  replace  its  amine  group  by  a  hydroxyl 
group  and  thus  effect  its  transformation.  It  is  a  matter  of 
importance  in  connection  with  the  question  of  sugar  forma- 
tion from  protein  that  the  amidized  sugar  group  in  the 
protein  molecule  is  not  capable  of  direct  and  immediate 
transformation  into  grape-sugar. 

We  have  no  proof  that  any  of  the  alcohols  or  of  the  acids 
of  the  sugar  group  (glyconic  acid,  saccharic  acid,  glycuronic 
acid)  take  part  in  glycogen  formation,  which  may  be  easily 
appreciated  when  it  is  recalled  that  their  transformation 
into  sugar  presupposes  complicated  oxidation  or  reduction 
processes. 

Formation  of  Glycogen  from  Formaldehyde. — Nor  has 

TIT 

Grube  's  statement 30  to  the  effect  that  formaldehyde,        | 

COH, 

which  to  all  appearances  plays  an  important  role  in  the  light- 
synthesis  of  sugar  in  plants,  is  formed  into  glycogen  when 
perfused  through  the  surviving  liver,  remained  without 
contradiction.31  A  synthetic  process  of  this  sort  would  not 
be  very  hard  to  imagine.  According  to  the  latest  studies  of 
R.  Przibram  and  A.  Franke,32  the  action  of  ultraviolet  light 
rays  upon  an  aqueous  solution  of  formalydehyde  is  sufficient 
to  produce  the  " simplest  sugar,"  glycolaldehyde,  as  well  as 
higher  condensation  products.  The  process  may  be  sup- 
posed to  follow  the  adjacent  schema  with  possible  eventual 
formation  of  sugar : 

FORMALDEHYDE      GLYCOLALDEHYDE  GLYCERINALDEHYDE 

H 

|  CH2.OH 

COH  CH2.OH              | 

+  — >   | >    CH.OH ► 

H  COH         H       | 

I  +   I       COH    + 

COH  COH 

Limit  of  Saturation  and  Utilization. — The  subject  of  as- 

30  K.  Grube  (Bonn),  Pntiger's  Arch.,  121,  636,  1908;  126,  585,  1909;  139, 
428,  1911. 

81  B.  Schöndorff  and  F.  Grebe  (Bonn),  Pflüger's  Arch.,  138,  525,  1911. 

32  R.  Przibram  and  A.  Franke,  Sitzungsber.  d.  Wiener  Akad.,  Mathem. 
Naturw.  Klasse,  71,  IIb,  Feb.,  1912. 


232  GLYCOGEN 

similation  limit  of  the  various  sugars  has  attained  consider- 
able importance  from  studies  which  have  been  conducted  in 
F.  Hofmeister 's  laboratory.33  Using  the  same  rabbit  in  a 
series  of  injections  of  varying  dosage  of  sugar  into  the 
auricular  vein  one  may  determine  the  dose  which  the  animal 
can  take  without  glycosuria  ensuing  in  the  course  of  a  few 
minutes.  This  amount,  determined  by  F.  Blumenthal  as  1.8 
to  2.8  grams  for  a  rabbit,  proved  repeatedly  for  the  individ- 
ual animal  remarkably  constant  (within  0.1  gram).  These 
figures,  an  expression  of  the  ability  of  the  body  to  take  up  the 
sugar  and  its  conversion  products  from  the  circulation  to  a 
point  of  saturation,  is  known  as  the  ' '  saturation  limit. ' '  It 
furnishes  a  useful  means  of  measuring  the  actual  appropri- 
ating power  of  the  body  for  any  given  time.  It  is  not  quite 
the  same  thing  as  the  "utilization  limit,"  which  is  de- 
termined by  finding  out  by  intermittent,  graded  sugar  injec- 
tions the  largest  amount  which  can  be  borne  continuously 
when  introduced  regularly  at  short  intervals  without  ensuing 
glycosuria.  Apparently  when  the  saturation  limit  has  been 
once  reached  by  a  large  administration  of  sugar,  a  very 
small  continued  additional  amount  is  sufficient  to  maintain  a 
glycosuria. 

It  may  be  readily  seen  that  an  alimentary  glycosuria 33a 
is  more  likely  to  occur  in  an  individual  whose  glycogen  de- 
posits are  excessive  from  previous  indulgence  in  carbo- 
hydrate food,  than  in  one  poor  in  glycogen;  and  that 
muscular  labor34  and  over  exposure  to  heat,35  by  increasing 
the  requirement  of  sugar,  raise  the  limit  of  assimilation.  A 
number  of  other  agencies  which  are  apt  to  modify  the 
assimilation  limit  will  be  taken  up  later. 

83  F.  Blumenthal  (F.  Hofmeister's  Lab.,  Strassburg),  Hofmeister's  Beitr., 
6,  329,  1905. 

33a  Literature  upon  Alimentary  Glycosuria:  A.  Magnus-Levy,  Handb.  d. 
Biochem.,  //',  323-327,  1909. 

34 G.  Comessati  (F.  Hofmeister's  Lab.,  Strassburg),  Hofmeister's  Beitr., 
9,  66,  1907;  Grober  (Stintzing  Clinic,  Jena),  Deutsch.  Arch.  f.  klin.  Med.,  95, 
137,  1909. 

35  H.  Hohlweg  and  F.  Voit  (Giessen),  Zeitschr.  f.  Biol.,  51,  491,  1908. 


FORMATION  OF  SUGAR  FROM  PROTEIN  233 

FORMATION  OF  SUGAR  FROM  PROTEIN 

Coming  next  to  one  of  the  great  fundamental  problems 
of  the  study  of  metabolism,  one  upon  which  biologists  from 
the  olden  times  of  Claude  Bernard  to  the  present  have  time 
and  again  tested  their  acumen,  we  have  to  consider  the 
question  of  the  formation  of  sugar  from  protein. 

Carbohydrate  Group  in  Protein  Molecule. — Long  after 
the  possibility  of  separation  of  a  reducing  compound  from 
mucinous  substances  was  known,  the  discovery  that  a  carbo- 
hydrate group  is  a  natural  component  of  the  proteins  was 
made  by  Pavy.  Friedrich  v.  Müller,  the  clinician,  and  his 
pupils  contributed  mainly  to  establish  the  fact  that  protein 
sugar  is  not  identical  with  glucose  or  any  of  the  other  typi- 
cal hexoses,  but  is  rather  an  amidized  sugar,  glucosamine, 
CH2(OH)  -  CH(OH)  -  CH(OH)  -  CH(OH)  -  CH(NH2)  - 
COH,  obtained  also  by  Ledderhose  by  cleavage  of  chitin.36 
While  mucins  and  many  mucoids  (as  the  egg  envelopes  of 
the  frog  and  of  cephalopods)37  are  about  one-third  made  up 
of  glycosamine,  and  the  amount  of  this  material  in  ovalbu- 
min, which  is  especially  rich  in  sugar,  is  commonly  estimated 
at  about  ten  per  cent.,  in  other  true  proteids  a  low  percentage 
or  only  a  fraction  of  one  per  cent,  is  present.  Many,  as  case- 
in, contain  no  carbohydrate  at  all.  (It  is  not  difficult  to  de- 
termine the  amount  of  carbohydrate  of  a  protein  if  the  latter 
is  hydrolyzed  by  boiling  with  a  mineral  acid,  by  separating 
from  the  mixture  the  substances  which  can  be  precipitated 
by  phosphotungstic  acid,  and  estimating  the  amount  of  sugar 
in  the  filtrate  in  the  usual  manner.)  The  expectation  of 
finding  in  the  carbohydrate  group  of  the  protein  molecule 
the  key  to  the  problem  of  forming  sugar  from  protein  soon 
proved  fruitless.  We  were  forced  to  recognize  very  soon 
that  the  quantity  of  proteid  sugar  cannot  by  any  means 

36 Literature  upon  the  Carbohydrate  Group  in  Protein:  L.  Langstein, 
Ergebn.  d.  Physiol.,  V ,  77-99,  1902;  3',  456-467,  1904;  O.  Cohnheim,  Chemie  der 
Eiweisskörper,  4th  ed.,  82-89,  1911. 

"0.  v.  Fürth  (F.  Hofmeisters  Lab.,  Strassburg,  and  Zoological  Station  at 
Naples),  Hofmeister's  Beitr.,  1,  252,  1901. 


234  FORMATION  OF  SUGAR  FROM  PROTEIN 

suffice  to  cover  even  a  small  fraction  of  the  large  amount  of 
sugar  which  the  body  under  certain  circumstances  is  capable 
of  producing  from  protein.  Before  long,  too,  the  previously 
mentioned  (v.  sup.,  p.  231)  fact  became  unexpectedly  appar- 
ent that  the  body,  which,  with  a  readiness  that  almost  smacks 
of  play,  performs  so  many  chemical  transformations  that 
put  to  shame  the  art  of  the  chemist,  is  unable  to  bring  about 
the  simple  substitution  of  the  amine  group  of  glucosamine  by 
a  hydroxyl  radical;  and  that  for  this  reason  glucosamine 
cannot  be  classed  among  the  typical  sugar-  and  glycogen- 
formers.  The  logical  conclusion  was,  therefore,  that  the 
sugar  which  in  human  diabetes,  pancreatic  diabetes,  phlorid- 
zin-diabetes,  etc.,  to  all  appearances  originated  from  proteins 
is  not  a  direct  hydrolytic  protein  cleavage-product,  but  must 
be  due  to  some  more  complicated  chemical  changes. 

Elimination  of  Sugar  and  Protein  Decomposition. — For 
several  decades  a  bitter  controversy  was  waged  upon  the 
question  of  accepting  the  reality  of  sugar  being  formed 
from  protein.  Most  prominent  of  all  its  opponents,  Edward 
Pflüger,  with  an  obstinacy  here  as  inseparable  from  the  char- 
acter of  this  great  physiologist  as  was  his  earnestness  in  the 
search  for  the  truth,  never  wearied  of  contesting  by  one  new 
ingenious  argument  after  another  against  the  doctrine  of 
sugar  production  from  protein ;  and  yet  in  the  end  he  was 
unable  to  prevent  the  theory,  well  founded  as  it  now  is,  from 
taking  a  permanent  place  in  our  science.  Today  the  details 
of  this  controversy  have  no  more  than  historical  interest; 
and  there  is  no  occasion  for  us  to  enter  into  the  matter  more 
fully  at  this  time.  It  will  probably  be  sufficient  to  briefly 
call  to  mind  the  steps  by  which  we  have  come  to  know  that 
sugar  may  be  formed  from  protein. 

For  this  we  are  indebted  primarily  to  a  long  series  of 
metabolic  researches  upon  human  diabetes,  and,  too,  upon 
pancreatic  diabetes  and  phloridzin  diabetes  in  animals,  with 
which  are  prominently  connected  the  names  of  Claude 
Bernard,  Külz,  Wolfberg,  Naunyn,  v.  Mering,  Minkowski, 


DECOMPOSITION  OF  PROTEIN  235 

Cantani,  Bendix,  Prausnitz,  Cremer,  Lüthje,  0.  Löwi,  Mag- 
nus-Levy, Graham  Lusk,  Friedrich  Kraus,  Mohr,  Falta, 
Gigon,  and  others.38  It  was  proved  time  and  time  again 
that  the  glycogen  supply  of  the  body  cannot  possibly  account 
for  the  large  quantities  of  sugar  excreted  in  the  urine ;  and 
the  many  observations  upon  the  relation  D  |  N  (Dextrose: 
Nitrogen)  indicate,  in  a  manner  which,  to  the  writer's  mind, 
must  be  convincing  to  any  unprejudiced  person,  that  there 
exists  a  relation  between  sugar  formation  and  protein  de- 
composition. Positive  statements  were  sure  to  be  given 
after  findings  like  those  of  Lüthje,39  who  fed  a  dog  whose 
pancreas  had  been  removed  upon  carbohydrate-free  diet  for 
a  protracted  period  and  in  the  end  found  that  four  times 
more  sugar  had  been  excreted  by  the  animal  than  could  have 
possibly  been  deposited  in  the  form  of  reserve  carbohydrate 
(following  Pflüger 's  maximal  figures  for  the  quantity  of 
glycogen  in  the  tissues).  Finally  even  the  indefatigable 
sceptic  of  Bonn  was  forced  to  acknowledge  that  the  sugar 
produced  by  a  diabetic  individual  could  not  possibly  come 
from  the  glycogen  constituent  of  the  body,  and  that  it  must 
arise  from  some  other  source  which  he  was  unwilling  to 
accept  as  protein  but  was  inclined  to  put  down  as  fat.  Later 
on  the  pros  and  cons  of  sugar  formation  from  fat  will  be 
taken  up ;  here  it  is  proper  to  say  only  that  Pflüger  did  not 
continue  in  this  interpretation.  He  found  in  dogs,  whose 
supply  of  glycogen  had  been  much  reduced  by  starvation 
and  phloridzin,  and  which  were  then  fed  upon  codfish  meat, 
which  is  very  poor  in  carbohydrates,  such  a  marked  ac- 
cumulation of  glycogen  in  the  liver  that  he  frankly  acknowl- 
edged it  as  due  to  the  formation  of  sugar  from  protein.40 

38  Literature  upon  Formation  of  Sugar  from  Protein :  M.  Cremer,  Ergebn. 
d.  Physiol.,  1,  872-887,  1902;  L.  Langstein,  ibid.,  1,  62-109,  1902;  3,  453-496, 
1904;  R.  Tigerstedt,  Nagel's  Handb.  d.  Physiol.,  1,  502-508,  1905;  E.  Weinland, 
ibid.,  2,  440^142,  1907 ;  A.  Magnus-Levy,  Handb.  d.  Bioehem.,  4',  340-345,  346- 
356,  1909;    J.  Wohlgemuth,  ibid.,  3',  165-166,  1910. 

89  H.  Lüthje,  Deutsch.  Arch.  f.  klin.  Med.,  79,  498,  1904. 

"  E.  Pflüger  and  P.  Junkersdorf,  Pflüger's  Arch.,  131,  201,  1910. 


236  FORMATION  OF  SUGAR  FROM  PROTEIN 

This  ended  the  first  act  of  this  eventful  scientific  drama. 
All  the  more  honor  to  the  investigator  to  whom  had  fallen 
the  role  of  the  "spirit  that  would  not  down,"  that  at  the 
close  of  his  arduous  life  he,  as  it  were,  went  over  to  the 
enemies'  camp ;  this  he  did  as  soon  as  he  was  persuaded  that 
there  was  where  the  truth  lay.  May  the  coming  generations 
forget  the  acerbities  and  the  many  unfriendly  words,  but  not 
forget  that  even  this  controversy  was  not  entirely  without 
value  and  that  Eduard  Pflüger  is  to  be  honored  for  what  he 
stood  in  science,  a  true  seeker  after  the  truth. 

Respiration  Experiments. — The  formation  of  sugar  from 
protein  has  also  been  determined,  aside  from  the  method  of 
feeding  experiments,  in  another  way,  by  respiration  experi- 
ments. It  has  been  proved  that  if  abundant  protein  be  fed 
after  a  previous  period  of  starvation  practically  all  of  the 
nitrogen  of  the  protein  employed  will  appear  in  the  excreta, 
but  a  portion  of  the  carbon  will  remain  in  the  body.  ' '  Here 
the  only  alternative,"  says  Max  Cremer,  "unless  one  is  will- 
ing to  take  refuge  in  unknown  and  hitherto  unproven  modes 
of  retention,  is  to  think  of  this  carbon  as  contributing  to 
form  either  glycogen  or  fat.  To  anyone  who  like  myself 
holds  the  formation  of  fat  in  a  strictly  synthetic  production 
only  as  succeeding  a  prior  stage  of  glucose  these  experi- 
ments are  thoroughly  conclusive  of  the  new  formation  of 
glucose. ' ' 

New  Formation  of  Carbohydrate  in  Gly  cog  en-free  Tis- 
sues.— Even  the  man  who  is  dissatisfied  with  such  observa- 
tions cannot  gainsay  the  fact  of  the  new  formation  of  glyco- 
gen in  the  starving  animal.  Rabbits  can  be  made  entirely 
devoid  of  glycogen  by  being  starved  for  a  number  of  days  and 
then  subjected  to  strychnine  convulsions.  If  such  glycogen- 
free  animals  are  allowed  to  starve  further  and  are  killed  at 
the  first  sign  of  the  premortal  increase  of  nitrogen  elimina- 
tion (indicative  of  the  complete  consumption  of  the  supply  of 
reserve  material  and  that  thereafter  the  protein  constituents 
of  the  tissues  are  of  necessity  being  drawn  upon),  they  will 


SUGAR  FORMATION  IN  GLYCOGEN-FREE  TISSUES    237 

again  be  found  to  contain  glycogen,  according  to  Roily.41 
Apparently  a  portion  of  the  mobilized  tissue  proteins  has 
been  changed  into  sugar.  In  the  same  way  new  formation 
of  carboh}Tdrate  occurs  in  glycogen-free  animals  if  an  in- 
crease in  protein  decomposition  be  induced  by  an  infectious 
fever  (produced  by  inoculation  with  bacterium  coli).42 
Pflüger  himself  proved  that  mere  starvation,  as  a  rule,  is 
incapable  of  ridding  the  body  of  glycogen,  because  glycogen 
will  be  newly  formed  from  substances  which  are  not  carbo- 
hydrates.43 G.  Embden 44  has  proved  that  a  marked  access 
of  sugar  occurs  when  the  living,  excised,  glycogen-free  liver 
of  a  dog  is  perfused,  referable  to  the  sugar  antecedents  in 
the  blood  or  in  the  liver ;  and  M.  Löwit 45  has  been  able  to 
show  that  the  glycogen-free  livers  of  cold-blooded  and  warm- 
blooded animals  under  proper  circumstances  can  form  sugar 
even  postmortem  (or  in  course  of  life  after  excision), 
although  postmortem  glyconeogenesis  could  not  be  proved 
for  the  blood  or  other  tissues.  It  is  safe  to  say  that  here, 
too,  we  can  tentatively  think  of  a  formation  of  sugar  from 
proteid  substances,  particularly  as  we  have  no  ground  for 
assuming  the  existence  of  any  sort  of  unknown  high  mole- 
cular carbohydrates  in  the  liver  different  from  glycogen. 
There  may  be  some  justification  in  placing  in  this  same  cate- 
gory certain  discoveries  referable  to  the  formation  of  sugar 
in  autolysis,  as  that  of  Seegen  in  which  sugar  was  said  to 
have  been  formed  from  peptone  in  portions  of  liver,  and  that 
of  Weinland,  who  assumed  that  sugar  was  produced  from 
protein,  supposed  to  have  taken  place  in  a  mush  of  fly-larva? 
when  oxygen  was  introduced.  It  should,  however,  be  ex- 
plicitly stated  that  the  former  of  these  findings  has  not  been 

"Roily,  Deutsch.  Arch.  f.  klin.  Med.,  83,  107,  1905. 

42  C.  Hirsch  and  Roily  (Med.  Clinic,  Leipzig),  Deutsch.  Arch.  f.  klin.  Med.. 
78,  380,  1903. 

-3E.  Pflüger,  Pflüger's  Arch.,  119,  117,  1907. 

**  G.  Embden,  Hofmeister's  Beitr.,  6,  44,  1903 ;  Biochem.  Zeitschr.,  6,  66, 
1904. 

"M.  Löwit  (Innsbruck),  Pflüger's  Arch.,  136,  572,  1910. 


238  FORMATION  OF  SUGAR  FROM  PROTEIN 

confirmed,46  and  that  Weinland 's  work,47  to  the  author's 
mind,  should  be  repeated  by  a  number  of  different  methods 
before  final  credence  can  be  given  it.48 

Formation  of  Sugar  from  Various  Proteins. — Consider- 
able work  has  been  expended  upon  the  question  of  the  rela- 
tion of  various  proteins  to  the  amount  of  sugar  which  they 
are  capable  of  producing  in  metabolism,  but  with  little  other 
result,  as  far  as  the  writer  can  observe,  than  the  fact  that 
the  quantity  of  carbohydrate  preformed  in  the  proteid  sub- 
stances (glucosamine)  is  by  no  means  striking.  Quite  re- 
cently experiments  have  been  repeated  in  M.  Cramer's 
laboratory  showing  in  comparative  feeding  tests  on  a  phlor- 
idzin  dog  with  meat  and  casein  (casein  is  a  carbohydrate- 
free  protein)  a  difference  in  favor  of  casein.49  The  amounts 
of  sugar  which  can  be  produced  from  protein  (based  on 
calculation  of  the  D|N  relation)  have  been  given  in  highly 
varying  proportion ;  incidentally  it  was  calculated  that  after 
feeding  meat  half  of  the  energy  of  the  protein  can  take  on 
the  form  of  sugar  and  can  be  stored  as  glycogen  for  future 
use.  Such  statements  cannot,  however,  as  yet  be  regarded  as 
final.50 

Origin  of  Sugar  from  Aminoacids. — Having  clearly  be- 
fore us  the  facts  of  sugar  formation  from  protein,  we  may 
proceed  to  the  question  of  the  chemistry  of  this  process. 

Explanation  of  the  mechanism  of  sugar  production  from 
protein  has  been  sought  by  administering  the  individual 
"building  stones"  of  protein,  the  aminoacids,  to  dogs  with 
pancreatic  diabetes  and  phloridzin  diabetes,  and  determin- 
ing their  influence  upon  sugar  elimination  and  glycogen 
formation.    Investigations  with  this  in  view  (particularly 


itt  Cf.  L.  Langstein,  Ergebn.  d.  Physiol.,  1',  108,  1902. 

47  E.  Weinland,  Zeitschr.  f.  Biol.,  W,  421-466,  1907. 

48  0.  Krummacher  and  E.  Weinland,  Zeitschr.  f .  Biol.,  52,  273,  1909. 

49  P.  Rohmer  (M.  Cremer's  Lab.),  Zeitschr.  f.  Biol.,  54,  455,  1911. 

50  Investigations  by  Külz,  Lusk,  Halsey,  Lüthje,  Bendix,  Berger,  Lehmann, 
Schumann-Leclerc,  Mohr,  Falta,  Therman,  G.  Müller  and  others.  Literature: 
P.  Rohmer,  1.  c. 


ORIGIN  OF  SUGAR  FROM  AMINOACIDS  239 

those  of  Röhmann,  R.  Colin,  Nebelthau,  Neuberg  and  Lang- 
stein,  Knopf,  Halsey,  F.  Kraus,  Enibden  and  Salomon, 
Glässner  and  E.  Pick  and  Graham  Lusk)51  have  led  to  the 
conclusion  that  sugar  production  from  aminoacids,  at  least 
from  glycocoll,  alanin,  asparaginic  acid  and  glutaminic  acid, 
cannot  well  be  doubted.  The  conceptions  framed  to  explain 
the  process  are  entirely  hypothetical.  The  synthesis  of 
sugar  may  possibly  take  place  through  the  formation  of  sub- 
stances containing  one,  two  or  three  carbon  atoms,  as 
formaldehyde,  glycolaldehyde  and  lactic  acid,  the  fitness  of 
which  for  taking  part  in  direct  construction  of  sugar  is  more 
or  less  to  be  expected.  The  author  personally  is  more 
sympathetically  attracted  to  such  a  conception  as  that  which 
supposes  leucin  to  be  decomposed  into  two  triple-carbon 
compounds  52  to  be  synthesized  into  sugar,  than  to  any  idea 
of  a  "stretching"  of  the  branched 

LEUCIN  LACTIC  ACID  GLUCOSE 

CH3  .CH3 
\/ 

C  H  CH, 

CH2  = >       2CH.OH  — — >       CeH^O« 

CH.NH2  COOH 

COOH 

six-carbon  chain  of  leucin  to  bring  about  its  transformation 
into  sugar. 

Ringer  and  Graham  Lusk53  by  the  employment  of  an 
excellently  adapted  method  succeeded  in  producing  in  dogs 
a  very  uniform  glycosuria ;  and,  after  the  D  |  N  ratio  in  the 
urine  had  become  constant,  fed  aminoacids  to  the  animals. 
By  measuring  the  resultant  increases  of  sugar  excretion 
they  concluded  that  glycocoll  and  alanin  can  be  all  utilized  in 
formation   of   sugar,   but   of   the   four   carbon   atoms    of 

51  Literature :   J.  Wohlgemuth,  Handb.  d.  Biochem.,  3',  165-166,  1910. 

63  Cf.  L.  Langstein,  Ergebn.  d.  Physiol.,  3',  473,  1904. 

53  A.  J.  Ringer  and  Graham  Lusk  (Cornell  Univ..  New  York),  Zeitschr.  f. 
physiol.  Chem.,  66,  106,  1910;  Jour.  Amer.  Chem.  Soc,  32,  671,  1910;  cited  in 
Centralis,  f.  d.  ges.  Biol.,  10,  No.  2348. 


240 


FORMATION  OF  SUGAR  FROM  FAT 


asparaginic  acid  and  of  the  five  of  glutaminic  acid  presum- 
ably only  three  are  available  as  material  for  sugar. 

The  following  schema  of  these  authors  may  perhaps 
prove  useful  as  guides  in  further  investigations : 


GLYCOCOLL 

GLYCOLALDEHYDE 

GLUCOSE 

3  CH2.NH2 

^ 

3  CH2.OH 

C6H1206 

COOH 

COH 

— >■ 

ALANIN 

LACTIC  ACID 

GLUCOSE 

CH3 

1 

CH3 

O  r^TT  «~»TT 

2  CH.NH2 

>■ 

'»w 

CeHi2Oe 

Z  UH.Uxl 
COOH 

p 

COOH 

ASPARAGINIC  ACID 

/3-LACTIC  ACID 

GLUCOSE 

COOH 

2  CH2 

l 

)- 

COOH 
2  CH2 

C6Hi208 

CH.NH2 
COOH 

CH.OH 

>■ 

GLUTAMINIC  ACID 

GLYCERINIC  ACID 

GLUCOSE 

2   COOH 

CH2 
CH2 

CH2.OH 

1 

^>. 

1 
2  CH  OH 

CaHi2Oe 

CH.NH2 

COOH 

^ 

COOH 

FORMATION  OF  SUGAR  FROM  FAT 

Having  adjusted  our  ideas  as  best  we  can  in  the  matter 
of  the  production  of  sugar  from  protein,  our  attention  should 
next  be  given  the  difficult  problem  of  the  formation  of  sugar 
from  fat. 

It  should  primarily  be  understood  that  we  are  dealing 
here  not  with  a  single  problem  but  with  two.  Fat  is  made 
up  of  two  components  (glycerine  and  higher  fatty  acids), 
and  it  is  essential  to  clearly  distinguish  the  production  of 
sugar  from  glycerine  from  that  involving  the  fatty  acids. 

Formation  of  Sugar  from  Glycerine. — As  far  as  the  first 
of  these  items  is  concerned,  we  can  be  very  brief.  Experi- 
ments have  been  frequently  made  in  which  glycerine  has  been 


SEEGEN'S  EXPERIMENTS  241 

administered  to  diabetic  human  beings  and  animals,  which 
have  proved  beyond  doubt  that  this  substance  is  a  true 
sugar-  and  glycogen-producer.54.  This  was  to  have  been 
expected  when  one  recalls  that  Emil  Fischer  by  condensation 
of  the  glyceroses,  resulting  by  simple  bromoxidation  from 
glycerine,  directly  obtained  sugar  (i-fructose) : 55 


CH2.OH  CHj.OH 

CH.OH      +      CO 
COH         .     CH2.OH 


CH2.OH 
CH.OH 
CH.OH 
CH.OH 

CH,.OH. 


However,  the  fact  that  glycerine  constitutes  but  a  small  part 
(about  one-tenth)  of  the  molecule  of  fat,  indicates  that  the 
difficult  part  of  the  general  problem  is  not  in  this,  but  in  the 
question  of  the  production  of  sugar  from  the  higher  fatty 
acids.56  Let  us  therefore  at  once  consider  the  fundamental 
facts  which  have  been  evolved  for  this  latter. 

Seegen's  Experiments. — Seegen's  conception  of  a  large 
volume  of  sugar,  originating  from  protein  and  fat  decom- 
position, passing  from  the  liver  by  the  hepatic  vein  and 
permeating  the  body,  has  not  withstood  criticism  any  more 
than  his  statements  (supported  by  Weiss)  of  the  existence 
of  a  process  of  an  autolytic  new-formation  of  sugar  in  bits 
of  liver  tissue  digested  with  fat  and  soaps.57  These  matters 
are  now  all  relegated  to  the  past. 

54  Van  Deen,  Lucksinger,  Weiss,  Salomon,  Külz,  Frerichs,  Cremer,  Lüthje. 
Literature  upon  the  Formation  of  Sugar  from  Glycerine:  M.  Cremer,  Ergebn.  d. 
Physiol.,  1'  888-890,   1902;    J.  Wohlgemuth,  ibid.,  3',   167,    1910. 

66  Arranged  without  reference  to  the  stereochemical  configuration. 

58  Literature  upon  the  Formation  of  Sugar  from  the  Higher  Fatty  Acids : 
M.  Cremer,  Ergebn.  d.  Physiol.,  1,  888-895,  1902;  A.  Magnus-Levy,  Noorden's 
Handb.,  1,  178-181,  1906;  Handb.  d.  Biochem.,  4'  345-346,  1909. 

57  A.  Montuori,  Ber.  d.  Acad.  Neapel,   1895,  cited  in  Handb.  d.  Biochem., 
3',  167,  1910;  M.  Jacoby  (Salkowski's  Lab.),  Virchow's  Arch.,  157,  255,  1897; 
E.  Abderhalden  and  P.  Rona,  Zeitschr.  f.  physiol.  Chem.,  ltl,  303,  1904. 
16 


242  FORMATION  OF  SUGAR  FROM  FAT 

Respiratory  Quotient  in  Diabetes. — Attempts  have  also 
been  made  to  prove  that  sugar  is  produced  from  fat  from 
a  study  of  the  ratio  of  the  respiratory  quotient  in  diabetes. 
It  is  well  known  that  the  respiratory  quotient,  the  ratio 
between  the  output  of  C02  and  the  intake  of  oxygen,  wheu 
combustion    of    carbohydrates    alone    is    in    process,    is 
?&=if   because  the  different  sugars  contain  H  and  0  in 
the  proportions   of  water   and  necessarily  no   oxygen  is 
needed  to  oxidize  the  hydrogen  into  water.    But  as  this  is 
involved  to  a  marked  degree  when  fat  (very  poor  in  oxygen) 
is  burned,  the  respiratory  quotient  falls  to  0.7  in  the  actual 
consumption  of  fat.     The  portion  of  oxygen  intake  which 
is  employed  in  the  oxidation  of  H  into  water  of  course  does 
not   appear   as    C02.      In  the  combustion  of   protein   the 
quotient  is  about  0.8.     What  may  be  expected,  however,  if  in 
a  diabetic  there  takes  place  transformation  of  higher  fatty 
acids  into  sugar  and  this  be  excreted  as  such?    As  there 
must  of  necessity  be  a  number  of  CH2  complexes  reformed 
into  CH.OH.,  a  considerable  amount  of  oxygen  will  be  re- 
quired ;  and,  as  the  new-formed  sugar  is  not  consumed  but 
is  excreted,  the  intake  of  oxygen  cannot  at  all  coincide  with 
the  C02  output.     It  is  evident,  therefore,  that  a  marked 
lowering  of  the  respiratory  quotient  must  manifest  itself. 
Magnus-Levy  has  calculated  that  the  respiratory  quotient 
will  of  necessity  fall  to  0.6  or  lower  under  such  conditions ; 
but  even  in  diabetes  of  severe  type  he  found  an  actually 
higher  proportion,  while  Pflüger,  taking  the  same  observa- 
tions as  his  basis  but  other  methods  of  calculation,  actually 
obtained  in  the  case  of  a  severe  diabetic  a  quotient  of  almost 
exactly  0.6,  and  believed  that  this  proved  beyond  doubt 
that  fat  is  a  source  of  sugar.58     Unfortunately  it  must  be 
acknowledged  that  the  elements,  which  have  been  basically 
assumed  for  calculation,  are  not  as  yet  established  with  the 

68  A.  Magnus-Levy,  Verhandl.  d.  physiol.  Ges.  Berlin,  March  1,  1904; 
Centralbl.  f.  Physiol.,  18,  373,  1904;  Zeitschr.  f.  klin.  Med.,  56,  83,  1905; 
consult  therein  the  Literature.    E.  PMger,  Pfliiger's  Arch.,  108,  473,  1905. 


HIGHER  FATTY  ACIDS  243 

certainty  which  is  essential  for  precision  in  a  physical  ex- 
periment of  this  sort. 

Sugar  Nitrogen  Quotient. — Further  evidence  of  the  for- 
mation of  sugar  from  fat  has  been  recognized  in  observations 
upon  the  sugar-nitrogen  quotient,  D  |  N.  In  many  cases  of 
severe  diabetes  in  man  and  the  lower  animals  such  large 
amounts  of  sugar,  in  comparison  with  the  nitrogen  output, 
have  been  met  that  protein  decomposition  does  not  seem 
sufficient  to  explain  the  sugar  production ;  and  it  has  seemed 
impossible  not  to  refer  it  in  part  at  least  to  formation  from 
fat.59  The  possible  correctness  of  this  mode  of  interpreta- 
tion cannot  be  well  denied;  but  such  observations  cannot 
readily  be  accepted  as  complete  proof,60  particularly  because 
fundamentally  in  these  conclusions  we  have  to  take  into 
consideration  the  tacit  assumption  that  the  nitrogen  output 
at  a  given  time  is  invariably  regarded  as  a  correct  indicator 
of  the  protein  decomposition  going  on  in  the  body. 
O.  Löwi61  has,  however,  called  attention  to  the  important 
point  that  this  assumption  does  not  always  obtain  in  full. 
Nitrogen  retention  in  the  body  may  exist  at  times,  and  it  is 
possible  that  the  protein  decomposition  may  be  actually 
greater  than  the  coincident  nitrogen  elimination  would 
indicate. 

Fat  Impoverishment  in  Phloridzin  Animals. — Kolisch's 
observation  that  white  mice  in  chronic  phloridzin  intoxica- 
tion (in  comparison  with  control  animals)  show  extensive 
impoverishment  of  fat,  is  distinctly  interesting,  but  not  at 
all  conclusive  from  this  standpoint.613 

Influence  of  the  Introduction  of  the  Higher  Fatty  Acids 
Upon  Sugar  Elimination. — It  might  be  supposed  that  the 

69  Observations  by  Rumpf,  Lüthje,  Hartogh  and  Schumm,  Rosenquist,  Mohr, 
Hesse.  Junkersdorf,  Pfltiger's  Arch.,  137,  269,  1910,  and  of  v.  Noorden's  school. 

80  Cf.  criticism  of  above  by  F.  v.  Müller,  Landergren  and  Magnus- Levy, 
Literature:  A.  Magnus-Levy,  v.  Noorden's  Handb.,  2d  ed.,  1,  178,  1906,  and 
Handb.  d.  Biochem.,  k ',  345,  1909. 

61  O.  Löwi  (Lab.  of  H.  H.  Meyer,  Marburg),  Arch.  f.  exper.  Pathol.,  47, 
68,  1902. 

OTaKolisch,  Wiener,  klin.  Wochenschr.,  19,  559,  1906. 


244  FORMATION  OF  SUGAR  FROM  FAT 

most  simple  and  direct  means  of  settling  the  question  of  the 
production  of  sugar  from  the  higher  fatty  acids  would  be  by 
determining  whether  on  introduction  of  a  large  quantity  of 
such  substances  into  a  diabetic  the  excretion  of  sugar  would 
be  increased.  In  the  great  majority  of  observations  with 
this  point  in  view,  not  only  has  such  increase  been  missed 
as  a  matter  of  fact,  but  in  addition  in  a  number  of  cases  there 
has  been  a  noted  lowering  of  the  sugar  excretion  after  ad- 
ministration of  fatty  acids  (interpreted  on  the  supposition 
that  the  combustion  of  the  latter  serves  to  protect  the  protein 
from  undergoing  destruction  and  in  this  way  reduces  the 
formation  of  sugar  from  the  protein).62  It  would,  however, 
be  another  mistake  to  regard  such  negative  results  as  a  satis- 
factory proof  that  formation  of  sugar  from  the  higher  fatty 
acids  is  impossible.  Reference  may  be  made  here  to  the 
interpretation  of  A.  Magnus-Levy,63  whose  perspicaciously 
conducted  investigations  have  distinctly  advanced  the 
physiology  of  metabolism  in  so  many  ways,  upon  these 
points:  ''In  contrast  to  the  conditions  prevailing  with 
varying  introduction  of  protein,  where  as  a  matter  of  fact 
every  addition  of  protein  occasions  a  corresponding  increase 
in  protein  exchange,  the  most  marked  addition  of  fat  in- 
creases but  little  the  fat  exchange.  Fat  does  not  in  any 
sense  displace  other  food  from  metabolism.  In  the  starving 
dog  it  replaces  the  previously  consumed  body  fat;  is  con- 
sumed in  its  place.  An  excess  is  deposited  almost  in  its 
total  amount  without  essentially  increasing  metabolism. 
.  .  .  We  can  also  subscribe  to  the  statement  here  outlined 
in  this,  that  fat  as  the  most  passive  of  all  the  foodstuffs 
always  takes  part  in  the  combustion  process  after  all  the 
other  foods,  after  protein,  the  carbohydrates  and  alcohol, 
and  takes  part  only  as  far  as  an  existing  demand  is  not 

62 L.  Mohr  (F.  Kraus's  Clinic,  Berlin),  Zeitschr.  f.  exper.  Pathol.,  2,  463, 
481,  1906;  E.  Pflüger,  Pfliiger's  Arch.,  108,  115,  1905;  S.  Bondi  and  E.  Rud- 
inger,  Wiener  klin.  Wochenschr.,  19,  1029,  1906;  F.  Maignpn,  Jour,  de  Physiol., 
10,  866,  1908;  cf.  therein  the  older  literature. 

63  A.  Magnus-Levy,  Handb.  d.  Biochem.,  k'  343-344,  1909. 


CONCLUSIONS  AS  TO  ORIGIN  FROM  FAT  245 

satisfied  by  some  other  material.  Other  things  being  equal 
it  is  always  easy  to  force  the  other  three  foods  into  metab- 
olism by  increasing  their  assimilation ;  but  this  is  impossible 
in  the  case  of  fat.  Increased  combustion  of  fat  occurs  in  the 
diabetic  animal,  which  is  kept  on  protein  and  fat  alone,  only 
when  protein  is  withdrawn.  As  a  given  degree  of  lowering  of 
protein  exchange  is  followed  by  a  decrease  in  sugar,  so  some 
degree  of  increase  of  sugar  elimination  would  be  entirely 
covered  after  increased  fat  combustion."  In  this  connec- 
tion it  may  be  stated  that  (as  in  a  case  of  very  severe  diabetes 
in  v.  Noorden's  clinic64)  after  administration  of  large 
amounts  of  fat  an  enormous  sugar  elimination  has  been  ob- 
served, the  sugar-nitrogen  ratio  (D|N)  reaching  the  extra- 
ordinary height  of  10.  Falta,  in  his  valuable  efforts  to  es- 
tablish the  rules  of  sugar  elimination  in  diabetes  mellitus, 
came  to  the  conclusion  that  many  facts  of  the  pathology  of 
metabolism  are  entirely  inexplicable  without  the  assumption 
that  sugar  may  be  formed  from  fat,  and  that  the  evidence  in 
favor  of  this  has  been  distinctly  enlarged  by  his  own  and  his 
associates '  investigations.65 

The  question  of  sugar  formation  from  fat  today  is  in 
about  the  following  status :  that  it  has  not  been  absolutely 
proved,  but  has  on  the  other  hand  not  been  disproved  or 
even  become  improbable.  Magnus-Levy 66  very  properly 
suggests  that  the  body,  as  shown  by  all  experiments  in  spon- 
taneous and  experimental  diabetes,  has  a  relentless  need  for 
carbohydrates  which  it  tries  to  satisfy  under  all  circum- 
stances. For  this  end  the  carbohydrate  supply  in  the  body 
first  comes  in  question;  thereafter  the  formation  of  sugar 
from  protein ;  and  only  in  the  third  place  the  formation  of 
sugar  from  fat.    If,  however,  the  position  be  taken  (and 

84  S.  Bernstein,  C.  Bolaffio,  v.  Westenrijk  (v.  Noorden's  Clinic,  Vienna), 
Zeitschr.  f.  klin.  Med.,  66,  Heft.  5/6,  1908;  cf.  also  W.  Falta  and  A.  Gigon, 
Zeitschr.  f.  klin.  Med.,  65,  326,  1908. 

65  W.  Falta  (v.  Noorden's  Clinic),  Zeitschr.  f.  klin.  Med.,  66;  separate,  p. 
7,  1908. 

MA.  Magnus-Levy,  Noorden's  Handb.,  2d  ed.,  1,  179,  1906. 


246  FORMATION  OF  SUGAR  FROM  FAT 

doubtless  there  may  be  much  said  for  it)  that  the  body  can 
execute  its  manifestations  of  energy  (in  a  certain  sense, 
render  its  cash  payments)  only  on  a  carbohydrate  stand- 
ard, the  assumption  of  sugar  formation  from  fat  is  still 
asserted  even  if  not  in  so  many  words ;  for  it  can  scarcely 
be  questioned  that  in  the  starving  animal  the  performance 
of  work  must  draw  upon  its  supplies  of  fat,  or  that  a  human 
being  in  a  long  continued  fever,  or  a  hibernating  marmot, 
undoubtedly  sustains  the  output  of  energy  for  the  most  part 
at  expense  of  its  body  fat.  If  in  such  examples  the  direct 
source  of  mechanical  and  thermic  energy  were  to  be  refer- 
able to  the  combustion  of  sugar  alone,  the  conclusion  must 
be  that  a  great  part  of  this  sugar  must  come  from  fat.  The 
problem  of  sugar  formation  from  fat  therefore  falls  in  a 
certain  sense  in  the  same  class  with  that  of  the  sources  of 
energy  of  the  living  body,  and  any  one  who  adheres  to 
Zuntz's  belief  (v.  Vol.  I  of  this  series,  p.  159,  Chemistry  of 
the  Tissues)  in  the  dynamic  equivalence  of  the  three  main 
classes  of  foods,  will  necessarily  refuse  to  acquiesce  in  the 
last  mentioned  argument. 

There  is  no  doubt  that  in  the  plant  in  the  germination  of 
its  oily  seed  (where  the  reserve  substances  in  the  cotyledons 
and  in  the  endosperm  furnish  the  material  for  the  growth  of 
the  embryonal  plant)  there  takes  place  a  transformation  of 
fat  into  carbohydrate  to  a  very  great  degree.  The  fat  that 
is  disappearing  from  the  reservoirs  of  reserve  substance 
actually  forms  the  material  from  which  the  cell-walls  of  the 
young  plants  are  built  up.  But  it  is  perhaps  not  apposite  to 
apply  facts  which  have  been  discovered  in  plant  physiology 
to  animal  metabolism.67 

"Literature  upon  the  Behavior  of  the  Fat  in  Germination  of  Oil-bearing 
Seeds:    O.  v.  Fürth,  Hofmeister's  Beitr.,  4,  430,  1903. 


CHAPTER  XI 

PANCREATIC  DIABETES— HUMAN  DIABETES 

PANCREATIC   DIABETES 

The  preceding  lectures  have  introduced  the  fundamental 
facts  of  carbohydrate  metabolism  well  enough  to  permit  us 
to  venture  into  one  of  the  most  interesting  but  at  the  same 
time  one  of  the  most  difficult  problems  in  the  study  of  metab- 
olism, that  of  pancreatic  diabetes. 

In  the  current  of  the  sciences,  just  as  in  the  life  of  man, 
there  are  periods  when  every  good  intention  and  the  most 
honest  effort  are  insufficient  to  make  any  decisive  and  pro- 
ductive progress  possible;  evil  days  when  ability  is  com- 
pelled to  employ  a  good  part  of  its  innate  energy  to  keep 
from  sinking  into  dejected  inefficiency.  Then  all  of  a  sud- 
den some  new  event  takes  place,  changes  the  situation  of 
affairs  and  brushes  aside  the  impediments  which  have  op- 
posed the  free  development  of  the  long  accumulated  latent 
energy.  And  at  once  a  period  begins  of  heightened,  feverish 
activity  that  endeavors  to  make  up  for  all  that  was  missed 
in  the  dull  times  of  stagnation. 

Discovery  of  Pancreatic  Diabetes. — One  of  these  for- 
tunate events  occurred  in  the  development  of  metabolism 
study  when  in  1889  Oskar  Minkowski  and  Josef  v.  Mering 
discovered  pancreatic  diabetes  in  Naunyn's  laboratory  in 
Strassburg.1 

At  the  same  time,  and  independently  of  the  authors  just 
named,  N.  de  Dominici,  in  Naples,  also  discovered  the  ex- 
istence of  pancreatic  diabetes  (an  example  of  the  strange 
law  of  the  doubling  of  events  which  often  has  appeared  even 
in  physiology,  probably  because  a  discovery  cannot  be  made 


1  Literature  upon  Pancreatic  Diabetes:  O.  Minkowski,  Ergebn.  d.  Pathol., 
1,  69,  1896;  C.  v.  Noorden,  Handb.  d.  Pathol,  d.  Stoffwechs.,  2d  ed.,  2,  38-43, 
1907;    A.  Biedl,  Innere  Sekretion,  pp.  375-399,  1910. 

247 


248  PANCREATIC  DIABETES 

before  the  times  are  ripe  for  it,  and  in  a  sense  it  is  in  the 
air). 

Although  it  must  be  reluctantly  confessed  (for  that  mat- 
ter it  would  be  recognized  all  too  soon  even  without  such  a 
confession)  that  to-day,  after  almost  a  quarter  of  a  century 
has  elapsed  since  this  discovery,  we  are  not  in  position  to 
offer  a  satisfactory  explanation  of  the  real  nature  of  pan- 
creatic diabetes,  yet  it  is  impossible  to  mistake  the  fruitful 
influence  which  even  this  single  possible  means  of  artificially 
producing  a  metabolic  disturbance  analogous  to  human  dia- 
betes has  had  on  the  whole  field  of  physiology  and  pathology 
of  metabolism. 

Interrupted  Extirpation  of  the  Pancreas. — It  is  well 
known  that  extirpation  of  the  whole  of  the  pancreas  is  requi- 
site to  produce  a  typical  pancreatic  diabetes,  and  that  the 
preservation  of  a  small  portion  of  the  gland  will  suffice  to 
prevent  this  metabolic  fault.  If  the  bulk  of  the  gland  is  re- 
moved and  the  rest  located  subcutaneously  diabetes  does  not 
ensue,  but  will  promptly  follow  with  all  its  symptoms  upon 
subsequent  removal  of  the  transplanted  portion.  The  fact 
that  it  is  possible  to  cause  a  diabetes  of  the  severest  form  by 
a  trivial  interference  requiring  but  a  few  minutes  for  its  com- 
pletion, in  which  the  peritoneal  cavity  is  not  opened  at  all  and 
in  which  there  can  be  no  question  of  irritation  of  the  system 
of  peritoneal  nerves,  eliminates  all  objections,  as  Minkow- 
ski 2  properly  suggests,  to  the  belief  in  a  direct  relation 
between  diabetes  and  loss  of  pancreatic  function.  An  inter- 
rupted process,  recently  suggested  by  Hedon,3  makes  the  ex- 
tirpation of  the  pancreas  in  the  dog,  which  is  by  no  means 
easy  of  technic,  decidedly  less  difficult.  It  is  best  in  carrying 
out  the  procedure  to  first  remove  only  the  gastrosplenic 
portion  of  the  gland  and  to  transplant  the  lower  part  of  the 
tail  of  the  organ  with  its  nervo-vascular  pedicle  under  the 

20.  Minkowski,  Pflüger's  Arch.,  Ill,  13,  1906. 

3E.  Hedon  (Montpellier),  Arch,  intern,  de  Physiol.,  10,  350,  1911;  cf. 
therein  Literature. 


FUNCTION  OF  THE  ISLANDS  OF  LANGERHANS     249 

skin,  with  the  intention  of  taking  it  away  some  time  later, 
after  recovery  is  assured.  It  seems  of  much  importance  for 
the  success  of  the  operation  that  the  separation  of  the  head 
of  the  pancreas  from  the  wall  of  the  duodenum  be  properly 
performed.  Hedon  strongly  advises  that  the  gland  be  torn 
away  from  the  bowel  wall  and  the  latter  curetted ;  a  tedious 
stoppage  of  hemorrhage  by  ligature  is  avoided,  a  more 
thorough  extirpation  is  accomplished,  and  necrosis  of  the 
intestine  prevented,  which  is  the  principal  point. 

A  very  severe  diabetes  is  invariably  thus  produced,  set- 
ting in  after  completion  of  extirpation  and  lasting  until  the 
death  of  the  experiment  animal  (two  to  four  weeks  later). 
A  diabetes  thus  produced  proceeds  in  typical  fashion  with 
symptoms  of  hyperglycemia,  polyphagia,  polydypsia,  poly- 
uria, wasting  and  acidosis.  After  partial  extirpation  a  dia- 
betes of  less  marked  severity  may  be  induced,  with  a  course 
of  perhaps  many  months'  duration,  which  if  total  extirpa- 
tion be  completed  later  on  will  at  once  change  to  a  severe 
type.  By  transplanting  pancreatic  tissue  into  the  spleen 4 
the  duration  of  life  of  a  dog  with  pancreatic  diabetes  has 
been  successfully  lengthened  to  a  very  distinct  degree. 

The  statement  of  Chauveau  and  Kaufmann  that  the  re- 
sult of  pancreatic  extirpation  may  fail  to  appear  if  the 
cervical  cord  be  divided  has  not  been  confirmed.  Even  if 
this  be  done  and  in  addition  the  vagus  and  sympathetic 
nerves  be  cut,  thus  completely  excluding  influences  from  the 
cerebral  centres,  the  glycosuria,  according  to  Hedon, 
appears.5 

Function  of  the  Islands  of  Langerhans. — In  the  literature 
upon  pancreatic  diabetes  a  very  large  part  is  devoted  to 
experiments  which  have  as  their  purpose  determination 
whether  the  function  of  the  organ  concerned  with  carbo- 
hydrate metabolism  is  connected  with  the  secreting  paren- 

4  Martina,  cited  by  Jacoby,  Einführung  in  die  experimentelle  Therapie, 
p.  136,  1910. 

BE.  Hedon  (Montpellier),  Arch,  intern,  de  Physiol.,  11,  195,  1911. 


250  PANCREATIC  DIABETES 

chyma  of  the  pancreas  or  with  the  ' '  islands  of  Langerhans. ' ' 
B.  A.  Kohn  classes  the  islands  of  Langerhans  along  with 
the  parathyroids,  the  epithelial  part  of  the  hypophysis  and 
the  cortex  of  the  suprarenal  glands,  among  glands  without 
duct  or  glandular  lumen. 

Here  it  may  be  sufficient  to  state  as  a  matter  of  reference 
that  U.  Lombroso  6  after  sifting  the  general  material  (col- 
lected experiments  with  ligature  of  the  ducts,  artificially 
induced  atrophy  of  the  parenchyma,  pathological  observa- 
tions and  studies  in  comparative  anatomy),  came  to  the 
conclusion  in  a  monograph  upon  the  subject  that  both  forms 
of  epithelial  tissue  of  the  pancreas,  acini  and  islands,  take 
part  in  internal  secretion.  Swale  Vincent,7  in  a  recent 
critical  review,  says:  " Whatever  may  be  found  out  in  the 
future  in  regard  to  the  true  function  of  the  islands  of 
Langerhans,  their  essential  anatomical  relation  with  the 
zymogenous  tubules,  the  many  transition  forms  met  in  all 
vertebrate  genera,  and  the  transformation  of  acini  into 
islands  and  vice  versa,  apparently  prove  conclusively  that 
the  islands  are  not  sui  generis,  but  that  they  are  integral 
constituents  of  the  ordinary  pancreatic  tissue.  Whether 
the  temporary  transformation  into  insular  tissue  means  a 
particular  specialization  of  function,  our  present  evidence 
does  not  indicate. ' '  In  the  author's  personal  opinion,  it  can 
no  longer  honestly  be  doubted,  in  view  of  the  recent  investi- 
gations of  Weichselbaum  (vide  infra),  that  the  anatomical 
cause  of  diabetes  is  to  be  sought  in  lesions  of  the  islets. 

Duodenal  Diabetes. — Some  years  ago  Pflüger  took  occa- 
sion to  use  the  observation  that  section  of  the  intramesen- 
teric  nervous  connections  between  the  pancreas  and 
duodenum  in  the  frog  may  under  certain  circumstances  give 
rise  to  a  glycosuria,  as  a  basis  for  calling  into  question  the 
existence  of  a  pancreatic  diabetes,  and  for  substituting  for 
the  latter  a  "duodenal  diabetes."     The  whole  discussion 


6U.  Lombroso,  Ergebn.  d.  Pbysiol.,  9,  1-89,  1910. 

J  Swale  Vincent,  Ergebn.  d.  Physiol.,  9,  489-495,  1910. 


DUODENAL  DIABETES  251 

growing  therefrom  has  proved  practically  fruitless,  and  was 
basically  altogether  superfluous  as  the  above  stated  observa- 
tions of  Minkowski  and  his  numberless  followers 8  permitted 
but  one  interpretation.  But  it  served  to  show  again  that 
if  a  single  bit  of  pancreas  completely  detached  from  its  nerv- 
ous comunications  be  left  it  will  suffice  to  prevent  the  appear- 
ance of  glycosuria.  The  whole  duodenum  can  be  excised 
from  a  dog,  as  Minkowski  had  already  shown,  without  pro- 
ducing diabetes,  provided  a  portion  of  the  pancreas  has  been 
transplanted  under  the  skin ;  but  if  the  latter  at  a  later  time 
be  removed  from  the  animal  the  diabetes  promptly  sets  in. 
Strictly  speaking  nothing  at  all  has  been  gained  in  this  whole 
campaign  fought  with  an  array  of  heavy  artillery  of  au- 
thority and  between  strategists  of  note,  except  the  reestab- 
lishment  of  a  fact  that  has  been  known  long  before,  that  of 
the  influence  of  nervous  irritations  of  all  sorts  (corrosion  of 
the  duodenum  or  ileum,  injection  of  nicotine  into  the  stomach, 
chilling)  to  cause  the  liver  to  discharge  its  supply  of  carbo- 
hydrate and  sometimes  give  rise  to  glycosuria.9 

We  know  conclusively  that  pancreatic  diabetes  is  possible 
not  only  in  many  mammalia,  but  also  in  birds,  turtles,  frogs 
and  fishes,  and  that  in  those  instances  in  which  a  true 
glycosuria  has  not  been  found  (as  in  many  birds  and  in 
sharks)  there  may  be  noted  at  least  a  distinct  hyper- 
glycemia.10     We  may  apparently,  therefore,   regard  the 

s  Lepine,  H6don,  Gley,  Thiroloix,  Caparelli,  Harley,  Schabad,  Cavazzani, 
S'andmeyer,  Selig,  Rumbolt  and  others;  ef.  Literature  in  A.  Biedl,  1.  c. ;  also 
E.  Hedon,  Jour,  de  Physiol.,  l-'t,  907,  1912. 

9E.  Pflüger,  Pflüger's  Arch.,  106,  181,  1905;  118,  265,  267,  1907;  119,  227, 
297,  1907;  122,  267,  1908;  123,  323,  1908;  124,  1,  529,  632,  1908;  128,  125, 
1909;  R.  Gaultier,  C.  R.  Soc.  de  Biol.,  64,  826,  1908;  A.  Herlitzka,  Pflüger's 
Arch.,  123,  331,  1908;  M.  Löwit,  Arch.  f.  exper.  Pathol.,  62,  47,  1908;  U.  Lom- 
broso,  Arch,  di  Farmac,  9,  146,  cited  in  Jahresber.  f.  Tierchem.,  40,  811,  1910; 
O.  Minkowski,  Arch.  f.  exper.  Pathol.,  58,  271,  1908;  S.  Rosenberg  (N.  Zuntz's 
Lab.),  Biochem.  Zeitsehr.,  18,  956,  1909;  Pflüger's  Arch.,  12,  358,  1909; 
H.  Eichler  and  H.  Silbergleit,  Berliner  klin.  Woohenschr.,  1908,  1172; 
W.  Tscherniachowski,  Zeitsehr.  f.  Biol.,  53,  1,  1909;  A.  Visintini  (Pavia),  Med. 
Kiin.,  1908,  1613 ;    E.  Zack,  Wiener  klin.  Wochenschr.,  1908,  82. 


252  PANCREATIC  DIABETES 

existence  of  pancreatic  diabetes  as  established  beyond 
peradventure. 

Does  the  Internal  Secretion  of  the  Pancreas  Pass  with  the 
Lymph  Through  the  Thoracic  Duct  into  the  Blood? — We 
may,  however,  proceed  farther  and  take  up  the  question 
whether  the  presence  of  an  internal  secretion  influencing  the 
carbohydrate  metabolism  can  in  any  manner  be  directly 
recognized  in  the  blood. 

At  the  outset  an  interesting  fact  observed  by  Biedl  n 
may  be  mentioned,  namely,  that  in  dogs  in  which  the  thoracic 
duct  is  tied  or  opened  through  a  fistula,  glycosuria  will 
usually  occur.  This  fact  has  been  verified  in  Gottlieb's 
laboratory,12  and  has  been  supplemented,  too,  by  clinical 
observations  of  the  occasional  coincidence  of  chyluria  and 
glycosuria.13  Naturally  one  feels  a  strong  temptation  to 
interpret  these  observations  on  the  hypothesis  that  the 
lymph  duct  is  carrying  to  the  blood,  a  secretion  originat- 
ing in  the  pancreas  the  cessation  of  which  occasions  the 
glycosuria;  but  it  cannot  be  settled  offhand  whether  the 
glycosuria  may  not  have  been  induced  in  some  very  differ- 
ent way  in  such  cases  (as  by  nervous  irritation,  etc.). 

Blood  Transfusion  and  Parabiosis. — Besides  there  is  at 
least  a  chance  that  this  "internal  secretion"  of  the  pancreas 
does  not  gain  entrance  into  the  general  circulation  indirectly 
by  way  of  the  lymph  passages,  but  directly  into  the  blood  ves- 
sels. It  is  true  the  blood  of  the  pancreatic  vein  has  shown 
no  influence  upon  sugar  elimination  in  a  dog  with  the  pan- 
creas removed.14  But  when  Hedon  united  two  dogs  by 
anastomosing  their  carotid  arteries,  one  deprived  of  its 

10  W.  Kausch  (Naunyn's  Clinic),  Arch.  f.  exper.  Pathol.,  37,  274,  1896; 
M.  Löwit  (Innsbruck),  ibid.,  62,  47,  1909;  V.  Diamara  (Siena),  Arch.  Ital.  de 
Biol.,  55,  94,  1911;    cf.  therein  the  Literature. 

UA.  Biedl,  Centralbl.  f.  Physiol.,  1898,  624;  Biedl  and  Th.  Offer  (R.  Pal- 
tauf's  Lab.),  Wiener  klin.  Wochenschr.,  1901,  1530. 

12  J.  L.  Tuckett,  Jour,  of  Physiol.,  41,  88,  1910. 

13  A.  Magnus-Levy,  Zeitschr.  f.  klin.  Med.,  66,  4S2,  1908;    67,  524,  1909. 

11  A.  Alexander  and  R.  Ehrmann  (Berlin  Pathol.  Instit.,  Dept.  Exp.  Biol.), 
Zeitschr.  f.  exper.  Pathol.,  5,  367,  1909. 


HEPATIC  FUNCTION  IN  PANCREATIC  DIABETES    253 

pancreas  and  diabetic  and  the  other  a  normal  animal,  and 
procured  thorough  commingling  of  the  blood  of  the  two  by 
"crossed  carotid  transfusion,"  there  was  occasioned  in  the 
normal  animal  only  a  transitory  glycosuria,  while  in  the 
dog  deprived  of  its  pancreas  (the  experiment  being  con- 
tinued a  sufficient  length  of  time)  the  glycosuria  disap- 
peared sometimes  but  returned  after  the  carotid  anasto- 
mosis had  been  separated.15  It  is  true  these  findings  are 
neither  constant  nor  entirely  convincing,  because  a  low- 
ering of  the  renal  secretion  takes  place  in  connection  with 
them.  Forschbach,  in  Minkowski's  Clinic,  was  more  for- 
tunate in  bringing  about  a  blood  mixture  by  an  ingenious 
expedient  by  which  he  joined  surgically  a  normal  dog  and 
one  with  pancreatic  diabetes  into  one  parabiotic  double 
animal.  In  this  experiment  there  not  only  occurred  a  low- 
ering and  actual  disappearance  of  the  glycosuria  in  case  of 
the  animal  with  pancreatic  diabetes,  "but  the  condition  of 
the  animals  scarcely  differed  from  that  of  health,  and  the 
disappearance  of  cachexia  suggests  the  idea  that  the  diabetic 
metabolic  fault  was  attacked  at  the  root."16  Basically  con- 
sidered one  can  readily  appreciate  that  in  such  a  pair  of 
animals  the  pancreas  of  the  normal  individual  with  its  in- 
ternal secretory  function  is  at  the  disposition  of  the  partner 
without  a  pancreas,  with  the  effect  that  the  resultant  symp- 
toms are  not  necessarily  manifested.  According  to  Carlson 
the  internal  secretion  can  apparently  pass  in  pregnancy 
from  the  foetus  into  the  blood  of  the  mother.17 

Formation  of  Glycogen,  Diastasic  Power  and  Formation 
of  Sugar  from  Carbohydrate-free  Material  in  the  Liver  in 
Pancreatic  Diabetes. — After  complete  extirpation  of  the  pan- 

15  E.  Hedon  (Montpellier) ,  C.  R.  Soc.  de  Biol.,  66,  699,  1909;  67,  792,  1909; 
68,  341,  1910;  72,  584,  1912;  Rev.  de  MeU,  30,  617,  1910. 

"J.  Forschbach  (Minkowski's  Clinic,  Greifswald),  Deutsch,  med. 
Wochenschr.,  1908,  910;  Arch.  f.  exper.  Pathol.,  60,  131,  1909;  cf.  also 
E.  Pflüger,  Pflüger's  Arch.,  12k,  633,  1908. 

17  A.  J.  Carlson  and  F.  M.  Drennan  (Chicago),  Amer.  Jour,  of  Physiol.,  28, 
391,  1912. 


254  PANCREATIC  DIABETES 

creas  there  is  always  seen  after  a  time  a  marked  impoverish- 
ment of  glycogen  in  the  canine  liver.  The  muscles,  especially 
the  heart  muscle,  always  retain  their  glycogen  supply  more 
obstinately  than  the  liver.  In  contrast  to  this  loss  of 
glycogen  from  the  large  depots  a  striking  glycogenic  infil- 
tration, according  to  Ehrlich,  may  be  noted  in  the  leucocytes ; 
which  is  to  be  interpreted  as  a  carbohydrate  engorgement 
of  these  cells  caused  by  the  enrichment  of  the  blood  serum 
with  sugar.  When  we  consider  the  dominant  position  of 
the  liver  in  carbohydrate  metabolism  we  cannot  be  far  wrong 
in  relating  the  real  nature  of  pancreatic  diabetes  with  a 
disturbance  of  the  glycogen  function  of  the  liver. 

Actually  what  does  the  inability  of  the  liver  to  fix 
glycogen  in  pancreatic  diabetes  (Naunyn  has  coined  the 
term  dyszooamylia  for  the  condition)  mean?  Primarily  it 
should  be  noted  that  the  dyszooamylia  applies  only  to 
dextrose,  not  to  hevulose,  Minkowski  having  shown  that 
formation  of  glycogen  from  the  latter  substance  may  con- 
tinue without  disturbance  even  in  the  severest  pancreatic 
diabetes.  According  to  the  investigations  of  J.  de  Meyer  18 
it  would  appear  that  the  surviving  liver  of  a  dog  with 
pancreatic  diabetes  may  be  found  capable  of  storing  glyco- 
gen provided  pancreatic  extract  is  added  to  the  perfusing 
fluid.  However,  we  can  by  no  means  assert  an  absolute  in- 
ability of  the  liver  to  form  glycogen  in  individuals  with 
pancreatic  diabetes,  as  Nishi 19  (in  a  research  under  the 
direction  of  0.  Löwi)  has  been  able  to  show  that  in  turtles 
with  pancreatic  diabetes  the  formation  of  glycogen  is  the 
same  as  in  normal  turtles  when  the  liver  is  perfused  with 
Ringer's  fluid  containing  glucose.  Here,  too,  matters  are 
by  no  means  simple. 

It  is  possible  that  an  interpretation  of  the  following  kind 

18  J.  de  Meyer  (Instit.  Solvay,  Brussels),  Arch,  intern,  de  Physiol.,  9, 
1,  1910. 

18 M.  Nishi  (Pharmacol.  Instit.,  Vienna),  Arch.  f.  exper.  Pathol.,  62, 
170,  1910. 


GLYCOLYSIS  255 

might  be  proposed:  that  the  liver  itself  is  not  actually  in- 
capable of  building  up  glycogen  in  pancreatic  diabetes,  but 
that  an  increased  activity  of  the  hepatic  diastasic  ferment 
(normally  kept  in  due  bounds  by  the  internal  secretion  of 
the  pancreas)  makes  it  impossible  that  the  glycogen  be  re- 
tained. But  apparently  after  extirpation  of  the  pancreas 
the  amount  of  diastase  in  the  blood  undergoes  reduction.20 
Statements  indicating  that  the  diastasic  power  of  the  liver 
is  increased  in  diabetes  21  are  contradicted  by  other  com- 
pletely negative  results.22  So  there  is  no  outlet  apparent 
in  this  direction. 

Pflüger  noticed  that  in  dogs  with  pancreatic  diabetes, 
with  marked  emaciation  and  their  fat  largely  lost,  the  liver 
in  contrast  with  other  organs  had  distinctly  increased  in 
weight.  This  suggests  that  the  hepatic  function  here  is 
not  depressed,  but  that  the  organ  really  is  working  under 
abnormal  stress  to  form  out  of  carbohydrate-free  material 
the  large  amounts  of  sugar  which  appear  in  the  urine.  Yet  in 
this  connection  it  may  be  noted  that  in  Embden's  laboratory 
in  the  artificially  perfused  liver  of  the  depancreatized  dog, 
practically  free  of  glycogen,  the  new  formation  of  sugar 
proved  to  be  no  greater  than  in  an  organ  freed  of  its  glycogen 
by  work  or  by  strychnia  convulsions.23 

For  the  present,  therefore,  we  possess  no  satisfactory 
explanation  for  the  mystery  of  pancreatic  diabetes  either 
in  the  formation  of  glycogen  in  the  liver,  its  diastasic  power, 
or  in  its  ability  to  produce  sugar  from  carbohydrate-free 
material. 

Glycolysis. — The  hypothesis  framed  by  Lepine  seems 
much  more  attractive.     The  pancreas  is  supposed  by  him 

20  W.  Schlesinger  (Vienna),  Deutsch,  med.  Wochenschr.,  1008,  593;  L.  K. 
Goult  and  A.  J.  Carlson  (Chicago),  Amer.  Jour,  of  Physiol.,  29.  165,  1911. 

21  A.  Hinselmann  (Med.  Clinic,  Heidelberg),  Zeitschr.  f.  physiol.  Chem., 
61,  265,  1909. 

22 1.  Bang,  Hofmeister's  Beitr.,  10,  320,  1907 ;  F.  A.  Bainbridge  and  A.  P. 
Beddard,  Biochem.  Jour.,  2,  89,  1907;  cf.  also  O.  J.  Wynhausen  (Amsterdam), 
Berlin,  klin.  Wochenschr.,  1910,  2107. 

23  L.  Lattes,  Biochem.  Zeitschr.,  20,  215,  1909. 


256  PANCREATIC  DIABETES 

normally  to  produce  a  glycolytic  ferment,  which  is  missing 
in  the  depancreatized  animal,  for  which  reason  the  animal  is 
unable  to  bring  the  sugar  to  its  usual  catabolism ;  the  sugar, 
therefore,  accumulates  in  the  blood  and  thence  passes  into 
the  urine.  The  original  idea  in  this  theory  which  would  seek 
to  place  glycolysis  normally  in  the  blood,  has  been  prac- 
tically altogether  given  up ;  our  present  conception  is  that 
the  sugar  undergoes  its  destructive  changes  for  the  most 
part  in  the  fixed  tissues,  not  in  the  blood. 

Otto  Cohnheim  24  believes  he  has  evidence  from  studies 
upon  the  expressed  juices  of  tissues  that  muscle  contains 
an  enzyme  which  is  capable  of  inducing  combustion  of  grape- 
sugar  to  carbonic  acid ;  which  however  does  not  exist  in  the 
muscle  in  active  form  for  the  most  part,  but  requires  for  ac- 
tivation a  material  arising  in  the  pancreas  and  passed  thence 
into  the  blood  stream,  a  "pancreatic  activator."  Occasion 
will  be  taken  later,  in  summing  up  our  conclusions  upon  gly- 
colysis, to  discuss  the  objections  which  have  been  made  to 
Cohnheim 's  experiments. 

In  view  of  the  undoubtedly  very  great  difficulty  of  posi- 
tively excluding  interference  from  bacterial  processes  in 
experiments  with  expressed  juices,  it  is  a  matter  for  special 
congratulation  that  certain  recent  comparative  experiments 
upon  the  consumption  of  sugar  by  the  normal  and  by  the 
diabetic  heart  by  one  of  the  best  of  our  living  biological 
experimenters,  E.  H.  Starling,25  are  available.  By  an  in- 
genious experimental  mechanism  he  has  succeeded  in 
arranging  a  heart  and  lung  preparation 26  so  as  to  keep  a 
dog's  heart  beating  for  hours,  working  at  normal  arterial 
pressure  and  maintaining  the  normal  amount  of  blood  in 

24  O.  Cohnheim,  Zeitschr.  f.  physiol.  Chem.,  39,  396,  1903;  42,  401,  1904; 
41,  253,  1906. 

25  F.  P.  Knowlton  and  E.  H.  Starling  (Univ.  College,  London),  Centralbl.  f. 
Physiol.,  26,  169,  1912;    Jour,  of  Physiol.,  45,  146,  1912. 

*  Cf.  E.  Jerusalem  and  E.  H.  Starling,  Jour,  of  Physiol.,  40,  299,  1910. 


OXIDATION  IN  DIABETES  257 

circulation.  As  shown  by  several  investigators,27  a  normal 
heart  in  beating  is  able  to  take  up  and  consume  a  not  incon- 
siderable amount  of  sugar  from  the  circulating  fluid. 
Starling  found  that  the  sugar  consumption  by  the  heart  of 
a  pancreatic-diabetic  dog  (transmitting  its  own  blood)  is 
minimal  or  practically  nil.  If,  however,  a  heart  from  an 
animal  with  pancreatic  diabetes  was  supplied  with  normal 
blood,  it  was  able  to  consume  sugar.  Moreover  when  a 
small  amount  of  pancreatic  extract  was  added  to  the  diabetic 
blood  there  always  followed  a  marked  rise  in  the  sugar  con- 
sumption in  the  diabetic  heart.  Starling  states  that 
"meanwhile  the  conclusion  seems  justified  that  normally  a 
hormone  is  produced  by  the  pancreas,  the  presence  of  which 
in  the  blood  is  essential  to  the  assimilation  and  utilization 
of  the  blood  sugar.  Our  experiments  are  proof  that  pan- 
creatic diabetes  is  more  likely  to  be  caused  by  a  diminished 
capacity  of  the  tissue  to  make  use  of  the  sugar  than  by  a 
primary  exaggeration  of  its  production. ' ' 28 

The  next  question  which  presents  itself  is  whether  we 
are  in  position  to  frame  some  reasonable  theory  as  to  the 
kind  of  disturbance  of  function  which  interferes  with  the 
tissues  consuming  the  sugar  in  a  normal  manner. 

Oxidation  Processes  in  the  Diabetic  Economy. — That  we 
are  not  dealing  here  with  a  diminution  of  the  oxidizing 
power  of  the  tissues  in  general  has  been  long  known.  On  the 
contrary,  recent  investigations  upon  animals  with  pancreatic 
diabetes  show  that  an  increased  consumption  of  oxygen  may 
be  regarded  as  a  characteristic  symptom  in  severe  diabe- 
tes.29 It  has  also  been  shown  that  the  first  products  of  sugar 
oxidation,  gluconic  acid,  glycuronic  acid  and  saccharic  acid, 

27  Chauveau  and  Kaufmann,  Locke  and  Rosenheim,  and  Rohde. 

28  In  reference  to  the  hypotheses  ( Chauveau,  Hedon,  Kaufmann  and  others ) 
which  attempt  to  refer  pancreatic  diabetes  to  an  increased  sugar  production 
dependent  upon  the  effectiveness  of  the  liver  and  of  the  central  nervous  system, 
see  A.  Biedl,  1.  c,  pp.  391-392. 

28  C.  v.  Voit,  Leo,  Weintraud,  Falta,  Grote  and  Stähelin,  Mohr;  for  Litera- 
ture consult  R.  Umber,  Lehrb.  d.  Ernähr.,  p.  138,  1909. 

17 


258  PANCREATIC  DIABETES 

undergo  combustion  readily  also  in  the  diabetic  organism 30 

GLUCOSE  GLUCONIC  ACID        GLYCURONIC  ACID      SACCHARIC   ACID 

CH2.OH        CH2.OH        COH         COOH 


(CH.OH)<      (CH.OH)4      (CH.OH)«       (CH.OH), 
COH         COOH        COOH        COOH 


(as,  too,  it  finds  no  difficulty  in  oxidizing  a  substance  as 
close  to  dextrose  as  glucosamine,  CH2.OH-  (CH.OH)3- 
CH.NH2  -  COH).31  It  might  possibly  be  thought  that  the 
diabetic  has  merely  lost  the  ability  to  manage  the  first  step 
in  sugar  combustion  (the  oxidation  of  glucose  into  gluconic 
acid).  If  that  were  the  case,  however,  it  would  be  difficult 
to  interpret  the  fact  that  diabetics  react  to  the  introduction 
of  chloral,  camphor,  etc.,  just  as  the  normal  individual  does, 
by  the  excretion  of  combined  glycuronic  acids.32  This  shows 
clearly  that  the  diabetic  has  the  power  to  carry  sugar 
oxidation  as  far  as  glycuronic  acid.  One  might  draw  the 
conclusion  from  this  that  normal,  physiological  combustion 
of  sugar  does  not  follow  the  path  through  gluconic  acid  and 
glycuronic  acid,  that  glycuronic  acid  is  only  produced  excep- 
tionally, if  occasion  demands  detoxification  of  some  foreign 
substance  or  other.  It  might  be  conceived,  too,  that  in  diabetes 
the  economy  still  retains  the  ability  to  oxidize  the  sugar  into 
glycuronic  acid,  but  loses  its  ability  to  effect  the  normal, 
physiological  catabolism  of  the  sugar  (presumably  disin- 
tegration of  its  molecule  into  compounds  with  two  or  three 
carbon  atoms,  like  lactic  acid). 

Metabolism  in  Pancreatic  Diabetes. — As  for  the  other 
metabolic  features  of  pancreatic  diabetes,  the  affection  is 
characterized  by  a  decided  increase  of  protein  and  fat  de- 
struction and  by  an  increased  elimination  of  the  mineral 

80  O.  Baumgarten  (Med.  Clinic  Halle),  Zeitschr.  f.  exper.  Pathol.,  2,  53, 
1905. 

31  J.  Forschbach  (Minkowski's  Med.  Clinic,  Cologne),  Hofmeister's  Beitr., 
8,  313,  1906. 

42  See  H.  G.  Wells,  Chemical  Pathology,  p.  530,  1907;  O.  Baumgarten, 
Zeitschr.  f.  exper.  Pathol.,  8,  206,  1910. 


METABOLISM  IN  PANCREATIC  DIABETES  259 

constituents.83  Acidosis  may  be  regarded  as  a  symptom 
resulting  from  the  destruction  of  fat  (accumulation  of 
,/?-oxybutyric  acid,  diacetic  acid  and  acetone),  which  is  met 
in  pancreatic  diabetes  as  well  as  in  severe  human  diabetes. 
Whether  these  features  are  entirely  and  satisfactorily  ex- 
plained on  the  basis  of  a  lowering  of  the  consumption  of 
sugar  (by  which  the  respiratory  quotient  is  diminished) 
must  for  the  present  be  left  unanswered.34 

From  the  above  it  might  be  expected  that  if  the  con- 
sumption of  sugar  in  a  dog  with  pancreatic  diabetes  be 
raised  by  physical  exertion  or  exposure  to  cold,  there  would 
result  a  lowering  of  the  sugar  elimination.  This  is,  how- 
ever, by  no  means  always  the  case,  as  shown  by  the  studies 
of  Embden  and  Lüthje.35  According  to  Minkowski,  in- 
creased sugar  consumption  from  physical  exercise  occurs 
only  if  some  functionable  remnant  of  the  pancreatic  tissue 
is  present  in  the  subject.  After  complete  exclusion  of  the 
pancreatic  function  it  seems  that  sugar  can  practically  no 
longer  be  utilized  to  defray  an  increased  demand  for  energy, 
and  at  best  the  latter  would  only  lead  to  a  heightened 
mobilization  of  sugar  at  the  expense  of  the  noncarbohydrate 
stores  and  therefore  (as  the  mobilized  sugar  is  not  oxidized 
but  excreted  unchanged)  to  an  increased  intensity  of  the  dia- 
betes. Heat  regulation  in  diabetic  animals  is  correspond- 
ingly encroached  upon  apparently. 

J.  de  Meyer,  from  a  study  conducted  in  Heger 's  labora- 
tory in  Brussels,  would  have  it  that  the  impermeability  of 
the  normal  kidney  to  sugar  is  related  with  the  internal 
secretion  of  the  pancreas.  If  Locke's  solution  containing 
about  the  same  proportion  of  sugar  as  occurs  in  the  blood 
be  perfused  through  the  fresh  (taken  from  a  dog)  kidney, 
sugar  passes  into  the  "  urine. "    On  adding  a  small  amount 

33  S.  la  Franca  (Naples),  Zeitschr.  f.  exper.  Pathol.,  6,  1,  1909. 

34  Cf.  F.  Verzär  (Tangl's  Lab.,  Budapesth) ,  Biochem.  Zeitschr.,  U,  201,  1912. 

35  H.  Lüthje,  Verh.  d.  22.  Kongress  f .  innere  Med.,  Wiesbaden,  1905,  268 ; 
G.  Embden,  H.  Lüthje  and  E.  Liefmann  (Frankfurt,  a.  M.),  Hofmeister's  Beitr., 
10,  265,  1907. 


260  PANCREATIC  DIABETES 

of  pancreatic  extract  to  the  circulating  fluid  this  "glyco- 
suria" diminishes  appreciably.  Other  tissue  extracts,  how- 
ever, apparently  have  no  specific  influence  upon  the  renal 
permeability.  Although  these  experiments  may  well  permit 
other  interpretations,  they  seem  to  deserve  further 
consideration  from  the  standpoint  in  view.36 

Partial  Extirpation  of  the  Pancreas. — Attention  should 
be  directed  to  the  recent  reports  upon  partial  pancreatic  ex- 
tirpation issued  by  F.  Beach 37  from  Durig's  laboratory.  A 
long  time  since  Sandmeyer  noted  an  increased  output  of 
sugar  in  dogs  after  partial  removal  of  the  pancreas  and 
administration  of  a  mixed  diet  of  raw  horsemeat  and  raw 
pancreas;  and  explained  it  on  the  supposition  of  an  aug- 
mentation in  the  utilization  of  the  glycogen  in  the  meat 
by  the  pancreatic  ferment.  Reach  has  shown  that  this 
explanation  is  not  correct,  but  that  the  raw  meat  (compared 
with  boiled  meat)  contains  a  poison,  labile  to  boiling,  which 
forces  up  the  sugar-excretion  in  slightly  diabetic  dogs. 

Antipancreatin  Serum. — One  can  readily  believe  that 
it  has  not  been  possible  to  entirely  resist  the  temptation 
of  applying  the  advances  in  immunology  to  the  great 
puzzle  of  pancreatic  diabetes.  That  the  blood  of  animals 
after  extirpation  of  the  pancreas  does  not  contain  any 
"toxine"  capable  of  rendering  normal  animals  diabetic  was 
shown  a  long  time  ago  by  Minkowski  and  Mering.  Accord- 
ing to  J.  de  Meyer,38  after  injection  of  extracts  of  dog  pan- 
creas (heated  previously  to  70°  C.)  a  supposedly  specific 
antibody  {"antipancreatin")  appears  in  the  blood  serum  of 
rabbits,  which  not  only  reduces  in  vitro  the  glycolytic  power 

36  J.  de  Meyer  (Instit.  Solvay,  Brussels),  Arch.  Internat,  de  Physiol.,  8, 
121,  1909;  Recherche  sur  la  signification  et  la  valeur  de  la  secretion  interne 
du  Pancreas,  Liege,  Imprimerie  H.  Vaillant-Carmanne,  1910. 

"  F.  Reach  (Durig's  Lab.),  Wiener  klin.  Wochenschr.,  1910,  No.  41; 
Biochem.  Zeitschr.,  S3,  436,  1911;  cf.  also  J.  Thiroloix  and  Jacob,  Bull,  et 
Mem.  de  la  Soc.  des  Höpit.  de  Paris,  1910,  492. 

88  J.  de  Meyer,  Arch,  internat.  de  Physiol.,  7,  317,  1909;  8,  121,  1909;  9,  1, 
1910;  10,  239,  1910;  11,  131,  1911;  Recherche  sur  la  signification,  etc.,  1.  c; 
Ann.  Instit.  Pasteur.,  22,  778,  1908. 


ISOLATION  OF  THE  "PANCREATIC  HORMONE"     261 

of  dog's  blood,  but  in  the  living  animal  induces  a  hyper- 
glycemia and  a  glycosuria  of  low  grade.  Objection  has 
been  raised  to  these  findings,  suggestion  being  made  that 
the  hyperglycemia  is  not  due  to  "antipancreatin"  but 
simply  to  withdrawal  of  the  blood  required  for  examination. 
The  writer  is  not  in  position  to  decide  whether  this  objection 
is  well  founded  or  not,  but  all  these  matters  are  so  compli- 
cated and  ambiguous  that  he  is  not  disposed  to  promise  any 
too  much  from  them  for  the  future  of  the  problem. 

Isolation  of  the"  Pancreatic  Hormone." — There  seems  to 
be  no  more  promise  in  the  attempts  to  isolate  the  active 
principle  of  the  pancreas  which  is  concerned  in  carbohydrate 
metabolism,  the  so-called  "pancreatic  hormone."  Realiza- 
tion of  the  pious  wish  to  solve  the  enigma  of  pancreatic 
diabetes  in  the  reagent  glass  seemed  almost  within  grasp 
some  few  years  ago  when  at  the  Congress  of  Internists  of 
1907  Zuelzer 39  excited  attention  by  his  announcement  that 
by  injection  of  pancreatic  preparations  it  is  possible  to  check 
the  course  of  adrenin  glycosuria,  and  by  administering 
pancreatic  substance  to  the  experiment  animal  prior  to  in- 
jection of  adrenin  to  prevent  it.  Based  upon  this  observa- 
tion, which  has  been  confirmed  from  many  sources,40 
Zuelzer41  later  endeavored  to  apply  the  discovery  to  the 
treatment  of  human  diabetes.  The  decided  toxicity  of  the 
pancreas  preparations  (occasioned  by  the  trypsin),  how- 
ever, interfered.  But  Zuelzer  believed,  nevertheless,  that 
by  a  method  which  he  kept  secret,  he  had  successfully 
detoxified  his  "pancreatic  hormone"  sufficiently  to  permit 
him  to  venture  to  inject  it  intravenously  into  diabetic  sub- 
jects.    In  a  number  of  cases  of  diabetes  he  succeeded  in 

39  Zuelzer,  Verb.  d.  Kongr.  f.  innere  Med.,  1907,  258;  Berliner  klin. 
Wochenschr.,  1907,  474. 

40  C.  Frugoni,  Makaroff,  J.  Gautrelet,  J.  Forschbach,  K.  Glässner  and  E.  P. 
Pick;  for  Literature,  cf.  0.  v.  Fürth,  and  C.  Schwarz,  Biochem.  Zeitschr.,  SI, 
114,  1911. 

"Zuelzer,  Dohrn  and  Marxer,  Deutsch,  med.  Wochenschr.,  1908,  1380; 
Zuelzer,  Zeitschr.  f.  exper.  Pathol.,  5,  307,  1909. 


262  PANCREATIC  DIABETES 

distinctly  reducing  the  elimination  of  sugar  and  of  acetone 
bodies.  However,  in  these  as  well  as  in  a  test  undertaken 
in  Minkowski's  Clinic,42  the  suggestive  fact  was  manifested 
that  injections  of  ''pancreatic  hormone"  were  often  fol- 
lowed by  chills,  fever  of  several  days '  duration  and  malaise. 
Still  later  the  writer's  colleague,  C.  Schwarz,  and  the 
writer 43  were  able  to  show,  at  least  in  case  of  intraperitoneal 
introduction  of  pancreatic  substance,  that  this  inhibition  of 
adrenin  glycosuria  is  not  due  to  a  mysterious  antagonism 
between  the  "hormones"  of  the  pancreas  and  of  the  adrenal 
glands,  but  probably  is  to  be  explained  naturally  and  easily 
as  depending  upon  a  condition  of  peritoneal  irritation  (v. 
Vol.  I  of  this  series,  p.  383,  Chemistry  of  the  Tissues).  This 
may  so  affect  the  secretory  ability  of  the  kidneys  that 
elimination  of  the  dissolved  constituents  of  the  urine  includ- 
ing sugar,  is  lowered  without  the  quantity  of  fluid  neces- 
sarily undergoing  any  coincident  striking  diminution.  When 
this  fact  is  considered  along  with  the  fact  that  a  great  variety 
of  disturbances,  perhaps  not  directly  related  with  the 
peritoneum  (as  fever,  suppression  of  urine,  introduction  of 
materials  with  lymphagogue  action,  etc.),44  are  capable  of 
inhibiting  adrenin  diabetes,  there  is  apparently  not  suffi- 
cient ground  here  for  a  pancreatic  treatment  of  diabetes.  If 
in  addition  the  statements  of  numerous  authors 45  are 
accepted,  that  injecting  and  feeding  pancreatic  substance 
not  only  does  not  arrest  the  glycosuria  in  animals  with 
pancreatic  diabetes,  but  in  many  instances  actually  intensi- 

42  J.  Forschbach  (Minkowski's  Clinic,  Breslau),  Deutsch,  med.  Wochenschr., 
1909,  No.  7. 

4S  0.  v.  Fürth  and  C.  Schwarz,  Wiener  klin.  Wochenschr.,  1911,  No.  4,  and 
Biochem.   Zeitschr.,  31,    113,    1911. 

"  Cf .  the  report  of  Mikulicich  upon  the  inhibition  of  adrenin  diabetes  by 
hirudin  (O.  Löwi's  Lab.,  Gratz),  Arch.  f.  exper.  Pathol.,  69,  128,  1912. 

41  Cf.  Literature  in  E.  Leschke  (Physiol.  Instit.,  Bonn),  Arch.  f.  Anat.  u. 
Physiol.,  1910,  401;  Münchener  med.  Wochenschr.,  1911,  No.  26;  cf.  also 
N.  Tiberti  and  A.  Franchetti  (Florence),  Lo  Sperimentale,  62,  81,  1908;  E.  L. 
Scott  (Carlson's  Lab.,  Chicago),  Amer.  Jour,  of  Physiol.,  29,  306,  1912. 


HUMAN  DIABETES  263 

fies  it,  Schwarz  and  the  writer46  (as  well  as  Leschke)  can 
scarcely  fail  to  be  justified  in  characterizing  the  efforts  to 
relieve  human  diabetes  by  intravenous  injection  of  "pancre- 
atic hormone"  as  physiologically  incorrect  and  (in  view  of 
the  danger  attending)  entirely  inadmissible.  Nor  can  the 
attempts  of  Vahlen,47  who  believes  he  has  isolated  a  sub- 
stance from  the  pancreas  which,  while  not  directly  attacking 
the  sugar,  accelerates  alcoholic  fermentation  of  the  sugar, 
and  lowers  the  sugar  excretion  in  phloridzin  diabetes  and 
adrenin  diabetes,  make  any  difference  in  their  conclusion. 
The  writer  feels  that  it  would  be  a  good  thing  to  consider 
carefully  the  above  stated  experiences  in  connection  with  the 
inhibition  of  glycosuria  by  administration  of  hydrazin,48 
opium,48  atropine,50  zyzigium  jambolianum  and  other 
drugs.51 

HUMAN  DIABETES 

Degeneration  of  the  Pancreas  in  Human  Diabetes. — We 
may  now  pass  to  the  consideration  of  human  diabetes. 

After  the  best  informed  experts  in  this  affection,  men 
like  Naunyn,  Minkowski  and  v.  Noorden,  as  well  as  nu- 
merous pathological  anatomists,  had  repeatedly  pointed  out 
a  relation  between  diabetes  and  some  functional  fault  of 
the  pancreas,  this  in  the  author's  opinion,  seems  to  have 
been  finally  proved,  whatever  the  contrary  opinions,  by  the 
comprehensive  investigations  of  the  Viennese  pathologist, 
Weichselbaum.  He  proved  from  a  large  amount  of  material 
at  his  disposal  that  degeneration  of  the  islands  of  Langer- 

4C  O.  v.  Fürth  and  C.  Schwarz,  1.  c. 

47  E.  Vahlen  (Halle),  Zeitschr.  f.  physiol.  Chem.,  59,  194,  1909. 

48  R.  P.  Underhill  and  M.  Fine  (Yale  Univ.,  New  Haven),  Amer.  Jour. 
Physiol.,  10,  271,  1911. 

40  A.  Gigon  (Basel),  Verh.  d.  26.  Kongr.  f.  innere  Med.,  Wiesbaden,  1909, 
p.  441. 

M  Cf.  Rudisch,  Arch,  f .  Verdauungskr.,  15,  469,  1909. 

61 M.  Mikulicich  (O.  Löwi's  Lab.,  Gratz),  Arch.  f.  exper.  Pathol.,  69,  133, 
1912,  holds  a  specific  renal  impermeability  for  sugar  responsible  for  the  inhi- 
bition of  adrenin  glycosuria  by  ergotoxin  as  well  as  for  inhibition  of  the 
hyperglycemia. 


264  HUMAN  DIABETES 

hans  is  to  be  looked  upon  as  the  anatomical  basis  of  diabetes, 
and  that  as  a  matter  of  fact  the  severity  of  the  case  stands 
in  direct  relation  with  the  degree  of  involvement  of  the 
islands.  Weichselbaum  differentiates  a  hydropic  degenera- 
tion of  these  structures,  a  peri-  and  an  intra-insular  sclerosis 
and  a  hyaline  degeneration,  the  last  characterized  by  swell- 
ing of  the  connective  tissue  about  the  vessels  of  the  islands 
into  a  homogenous  mass.  The  negative  findings  of  other 
authors  in  this  line  may  be  satisfactorily  explained  by  the 
fact  that  these  changes  may  very  readily  be  overlooked,  if 
particularly  attentive  examination  be  not  made  and  if  im- 
perfect preservation  of  the  material  has  obtained.52 

As  far  as  the  cause  of  the  pancreatic  disease  is  con- 
cerned many  authors  are  disposed  to  believe  that  a  relation- 
ship with  previous  acute  infectious  diseases,  although  cli- 
nically this  can  only  rarely  be  proved,  is  more  important  than 
the  influence  of  arteriosclerosis,  alcoholism,  syphilis,  intes- 
tinal infections,  etc.53  That  infectious  diseases,  even  those 
of  frankly  mild  type  as  influenza  or  angina,  may  make  exist- 
ing diabetes  permanently  worse  and  that  transient  glycosu- 
rias often  occur  in  the  course  of  febrile  affections  has  been 
long  known.  Doubtless,  too,  from  the  studies  of  Weichsel- 
baum, arteriosclerosis  plays  an  important  role  in  many 
forms  of  diabetes. 

The  liver  has  frequently  been  examined  for  anatomical 
changes  in  diabetes ;  but  there  can  be  little  mistake  in  believ- 
ing that  in  the  great  bulk  of  cases  in  which  diabetes  has 
appeared  as  a  sequel  of  hepatic  disturbances,  as  cirrhosis 
or  cholelithiasis,  secondary  lesions  of  the  pancreas  are  the 
real  point  in  fault.  Thus  we  may  appeal  to  the  frequent 
connective  tissue  hyperplasia  in  the  pancreas  in  connection 
with  cirrhosis  of  the  liver  (chronic  pancreatitis  of  Hanse- 

52  A.  Weichselbaum,  Wiener  klin.  Wochenschr.,  24,  153;  Sitzungsber.  d. 
Wiener  Akad.,  119,  III,  73,  1910;  consult  therein,  and  also  in  U.  Lombroso, 
Ergebn.  d.  Physiol.,  9,  1-89,  1910,  the  Literature. 

M  Cf .  F.  Hirschfeld,  Deutsche  med.  Wochenschr.,  1909,  137. 


GLYCOGEN  CONTENT  OF  THE  LIVER  265 

mann) ;  and  in  the  occasional  cases  of  diabetes  in  which 
previous  examinations  have  found  a  cirrhosis  of  the  liver 
along  with  an  apparently  normal  pancreas,  it  is  very  ques- 
tionable whether  there  did  not  exist  the  above-mentioned 
hydropic  changes  of  the  islands  of  Langerhans,  described  by 
Weichselbaum,  which  are  so  difficult  of  recognition.54  No 
doubt  nervous  lesions  of  very  many  types  may  give  rise 
to  glycosuria  and  be  causative  of  true  diabetes;  and  we 
may  accept  as  a  fact  that  nervous  irritations  are  capable  of 
inducing  a  liquidation  of  the  glycogen  stored  in  the  liver, 
as  seen  in  case  of  the  experimental  sugar  puncture.  This 
does  not,  however,  at  all  affect  our  referring  true  human 
diabetes  to  the  pancreas. 

We  are,  therefore,  fully  justified  from  the  present  status 
of  our  knowledge  in  regarding  human  diabetes  as  a  special 
type  of  pancreatic  diabetes. 

The  writer  can  scarcely  be  expected  to  enter  into  any 
detailed  description  of  this  affection,  the  literature  of  which 
is  enough  to  fill  a  whole  library ;  it  will  probably  suffice  if  a 
few  points  are  brought  out  which,  considered  from  the 
standpoint  of  a  biological  chemist,  seem  for  the  time  to  be  of 
special  interest,  and  to  refer  for  the  rest  to  Naunyn's 
classical  work  upon  diabetes  55  and  to  the  recent  excellent 
monographs  by  vonNoorden,56  Magnus-Levy,57  and  Umber.58 

Glycogen  Content  of  the  Liver. — A  point  requiring  at 
least  brief  consideration  is  the  amount  of  glycogen  found  in 
the  liver  in  human  diabetes.  As  previously  stated,  Naunyn 
assigned  to  "dyszooamylia"  an  important  position;  and 
most  writers  are  of  the  impression  that,  in  severe  diabetes 
at  least,  the  power  of  the  liver  to  store  glycogen  has  been 

64  Cf.  F.  Umber,  Lehrb.  der  Ernähr,  u.  Stoffwechselkr.,  p.  161,  1909. 

65  Naunyn,  Diabetes  Mellitus,  2d  ed.,  Vienna,   1900. 

MC.  v.  Noorden,  Die  Zuckerkrankheit,  5th  ed.,  1910;  Handb.  d.  Pathol,  d. 
Stoffwechsels,  2,  1-113,  1907. 

17  A.  Magnus-Le'vy,  Handb.  d.  Biochem.,  4',  356,  et  seq.,  1909. 
68  F.  Umber,  1.  c,  pp.  149-241. 


266  HUMAN  DIABETES 

more  or  less  seriously  disturbed.59  Remembering  the 
rapidity  of  postmortem  disappearance  of  glycogen  and  the 
fact  that  the  small  amount  of  intake  of  nutrition  before 
death  may  also  influence  the  amount  of  glycogen  in  the  liver, 
it  is  naturally  somewhat  difficult,  to  say  the  least,  to  come 
to  any  precise  conclusions  in  a  human  diabetic  as  to  his 
glycogen  stock.  The  noted  clinician,  Frerichs,  satisfied  his 
curiosity  in  this  respect  (by  a  very  direct  method,  but  one 
scarcely  to  be  commended  for  general  use)  by  removing 
during  life  bits  of  liver  tissue  by  puncture  in  two  cases  of 
diabetes ;  one  of  the  specimens  contained  glycogen.  When 
we  recall  that  diabetic  patients  are  able  to  change  laevulose 
into  glycogen  more  readily  than  they  can  transform  glucose, 
it  is  very  suggestive  that,  as  a  study  in  the  Vienna  Phar- 
macological Institute60  indicates,  a  rabbit's  liver  damaged 
by  phosphorus  poisoning  makes  a  like  differentiation  be- 
tween dextrose  and  laevulose ;  this  particular  power  of  dif- 
ferentiation is,  therefore,  by  no  means  a  characteristic  of 
diabetes  exclusively. 

It  has  been  previously  stated  that  quantitative  examina- 
tion of  the  diabetic  liver  for  its  diastase  has  not  led  to 
definite  conclusions. 

Hyperglycemia. — Hyperglycemia  in  diabetic  cases  is  gen- 
erally accepted.  While  the  amount  of  sugar  in  the  blood 
of  a  normal  human  individual  amounts  to  about  0.1  per  cent., 
the  proportions  in  the  diabetic  have  been  noted  as  high  as 
one  per  cent,  or  even  more.  This  in  itself  is  sufficient  reason 
for  the  presence  of  a  considerable  amount  of  sugar  in  the 
cerebrospinal  fluid  (obtained  by  lumbar  puncture) ;  notably, 
the  highest  figures  (as  high  as  three  per  cent.)  having  been 
met  in  comatose  cases  the  urine  of  which  contained  only 
moderate  amounts.61 

Methylene-Blue  Reaction  of  the  Blood. — This  character- 

■*Cf.  Literature:    A.  Magnus-Levy,  1.  c,  pp.  357-358. 

60  E.  Neubauer  (Pharmacol.  Instit.,  Vienna),  Arch.  f.  exper.  Pathol.,  61, 
174,  1909. 

"  N.  B.  Foster,  Boston  Med.  and  Surg.  Jour.,  158,  441,  1905. 


URINARY  DEXTRINE  267 

istic  color  reaction  of  the  blood  in  diabetes  is  supposed  to 
be  due  to  the  hyperglycemia.  It  has  been  noted  that  diabetic 
blood  has  the  property  of  changing  the  color  of  methylene- 
blue  to  a  yellowish  red,  apparently  by  some  reduction 
process.  Naturally  it  was  supposed  that  the  phenomenon 
is  referable  to  the  reducing  power  of  the  sugar  in  the  blood. 
However,  it  was  found  that  the  red  corpuscles  of  a  diabetic, 
after  they  have  been  entirely  freed  from  the  sugar-contain- 
ing plasma  by  repeated  centrif  ugation  with  isotonic  salt  solu- 
tion, fail  to  give  the  normal  appearance  of  erythrocytes 
(when  stained  with  methylene-blue) .  It  is  said,  too,  that  this 
blood  test  may  be  met  in  cases  long  after  the  sugar  has  dis- 
appeared from  the  urine  from  withdrawal  of  carbohydrates. 
It  may  be,  of  course,  that  even  in  such  cases  the  proportion 
of  sugar  in  the  erythrocytes  is  abnormally  high.  C.  v.  Noor- 
den  properly  calls  attention  to  the  need  of  making  quantita- 
tive comparisons  between  the  proportion  of  sugar  in  the 
blood  and  staining  qualities  in  order  to  gain  an  explanation 
of  this  reaction.62 

Another  question  which  is  connected  with  the  hyper- 
glycemia is  whether  the  increased  proportion  of  sugar  in 
the  blood  in  diabetes  is  necessarily  due  to  an  increased 
"impermeability  of  the  kidneys  for  sugar." 

urinary  Dextrine. — Very  little  attention  has  been  given 
to  the  question  whether  besides  the  sugar  it  is  possible  that 
polymeric  carbohydrates  may  also  pass  from  the  blood  into 
the  urine  in  diabetes.  Alf  tan 's63  estimations  of  an  aver- 
age excretion  of  0.15  gram  of  "urinary  dextrine"  for  a 
normal  man  and  in  severe  diabetes  of  perhaps  from  5  to  24 
grams  per  diem  apply  here.  The  exact  meaning  of  this 
"urinary  dextrine,"  chemical  study  of  which  is  as  yet 
lacking,  is  another  problem. 

8aC.  v.  Noorden,  Handb.  d.  Pathol,  d.  Stoffw.,  2d  ed.,  2,  104-105,  1907; 
cf.  therein  Literature. 

85  K.  v.  Alftan,  Ueber  dextrinartige  Substanzen  im  diabetischen  Harne, 
Helsingfors,  1904. 


268  HUMAN  DIABETES 

Protein  Destruction.— In  trying  to  come  to  some  reason- 
ably clear  appreciation  of  the  general  course  of  metabolism 
in  diabetes  we  must  take  prominently  in  consideration  what 
is  known  of  protein  destruction  in  this  abnormal  condition. 
While,  as  has  been  noted  above,  in  the  pancreatic  diabetes  of 
the  dog  the  decomposition  of  tissue  proteins  is  apparently 
markedly  increased,  in  severe  cases  of  diabetes  mellitus  (as 
shown  by  the  metabolic  studies  of  Falta  and  Gigon)  64  the 
destruction  of  protein  does  not  proceed  any  more  rapidly, 
and  in  special  cases  may  be  slower,  than  in  normal  persons 
who  are  examined  under  the  same  condition  of  nutrition. 
This  is  all  the  more  remarkable  when  one  considers  that  the 
diabetic  patient  undoubtedly  fixes  a  distinctly  smaller 
amount  of  material  as  reserve  carbohydrate,  and  that  the 
sugar  excreted  with  the  urine  escapes  combustion  and  can- 
not, therefore,  serve  to  save  the  protein.  The  loss  is 
apparently  compensated  for  as  far  as  possible  by  abundant 
intake  of  food  protein.  That  the  carbohydrate  group  in 
proteins  is  not  of  very  great  importance  to  the  formation 
of  sugar  in  the  body  has  been  shown  to  be  true  in  case  of 
human  diabetes  just  as  in  other  forms  of  glycosuria,65 

Falta 66  based  his  calculations  upon  the  "excretion  coef- 
ficient, ' '  that  is,  the  ratio  of  sugar  excretion,  D,  to  the  sugar 
value  of  the  transformed  material.  He  obtains  this  by 
the  formula  q=  ,  in  which  N  is  the  amount  of  urinary 

nitrogen  and  K  the  quantity  of  carbohydrate  in  the  food 
ingested.  This  method  of  calculation  is  based  upon  Eub- 
ner's  dictum  that  for  each  gram  of  transformed  protein 
nitrogen  a  maximum  of  five  grams  of  sugar  are  produced 
(that  is  to  say,  the  sugar  value  of  100  grams  of  protein 
would  be  roughly  16  X  5  =  80  grams  of  dextrose). 

That  a  combustible  material  like  alcohol  may  serve  to 

84  W.  Falta  and  A.  Gigon  ( W.  His's  Clinic,  Basel,  and  C.  v.  Noorden's  Clinic, 

Vienna),  Zeitschr.  f.  klin.  Med.,  65,  3-4,  1908. 

95  Cf.  E.  Thermann   (Helsingfors),  Skandin.  Arch.  f.  Physiol.,  17.  1,  1905, 
68  W.  Falta,  J.  H.  Whitney   (v.  Noorden's  Clinic),  Zeitschr.  f.  klin.  Med., 

65,  5-6,  1908. 


FATTY  DIABETES  269 

spare  the  proteins  of  the  body  and  in  this  way  lessen  the 
sugar  elimination  at  times  in  diabetics  6T  is  easily  appreci- 
able; as,  too,  the  fact  that  an  influence  tending  to  cause 
tissue  break-down,  as  exposure  to  Röntgen  rays,  is  likely 
to  occasion  an  increase  in  the  glycosuria  in  diabetes.68 

There  seem  to  be  times  when  aminoacids  pass  into  the 
urine  in  diabetes  in  increased  amount;  but  little  certain 
knowledge  is  had  of  this  phenomenon.69 

While  to  a  certain  extent  toxic  protein  decomposition 
in  human  diabetes  is,  from  what  has  been  said,  a  matter  of 
minor  importance,  the  fat  breakdown  often  dominates  the 
general  situation.  This  is  really,  as  far  as  we  can  readily 
appreciate,  what  is  actually  meant  when  we  are  forced  to 
say  that  the  body  must  finally  draw  on  some  source  to  cover 
the  necessary  requirements  for  energy-production ;  if  the 
sugar  is  eliminated  unconsumed,  if  the  tissue  protein  is 
preserved  from  destruction,  and  if  the  food  protein  is  insuf- 
ficient, there  is  nothing  else  left  the  body  to  draw  upon 
except  its  stores  of  fat.  Many  writers  are  inclined  to 
accept  a  possibility  of  sugar  being  formed  from  fat  in 
severe  diabetes.70  Later,  in  connection  with  acidosis  in 
relation  to  fat  decomposition,  this  subject  will  be  more  fully 
reverted  to. 

Brief  reference  should  be  made  at  this  point  to  the  rela- 
tionship of  obesity  to  diabetes.  Very  frequently  in  litera- 
ture a  "lipogenic  diabetes"  (diabete  gras  of  the  French) 
is  spoken  of.  C.  v.  Noorden71  has  suggested  a  very 
plausible  idea  in  this  connection,  that  there  exists  a  form  of 
masked  diabetes  in  which  the  sugar  does  not  pass  into  the 
urine  even  though  the  capacity  for  sugar  combustion  is 

67  H.  Benedict  and  B.  Török,  Zeitschr.  f.  klin.  Med.,  60,  329,  1906. 

"  P.  Menetrier  and  A.  Touraine,  Arch.  Maladies  de  Coeur,  8,  641,  1910. 

69  P.  Bergell  and  F.  Blumenthal,  Zeitschr.  f.  exper.  Pathol.,  2,  413,  1906; 
L.  Mohr,  ibid.,  2,  665,  1906. 

70 Cf.  E.  Gräfe  and  Ch.  G.  L.  Wolf  (Med.  Clinic,  Heidelberg),  Deutsch. 
Arch.  f.  klin.  Med.,  101,  201,  1912. 

71  C.  v.  Noorden,  Handb.  d.  Pathol,  d.  Stoffwechs.,  2d  ed.,  2,  25-26,  1907. 


270  HUMAN  DIABETES 

diminished;  in  such  cases  the  excess  of  sugar  is  changed 
into  fat  and  deposited  as  such.  A  ' ' diabetogenous  obesity' T 
of  this  sort  may,  if  glycosuria  come  to  accompany  it,  be 
changed  into  the  ordinary  diabetes  of  the  obese,  and  in  the 
end  into  a  severe  diabetes,  with  development  of  a  progressive 
loss  of  flesh. 

Diabetic  Lipcsmia. — Finally  among  the  disturbances  of  fat 
metabolism  noted  in  diabetes,  diabetic  lipsemia 72  presents 
special  interest.  While  the  quantity  of  lipoid  substances 
in  the  blood  plasma  is  normally  scarcely  more  than  one  per 
cent.,  in  diabetes  it  may  rise  to  many  times  this  proportion. 
Cases  have  been  known  in  whom  the  blood  from  the  veins 
looks  like  chocolate  and  cream,73  and  in  whom  the  vessels 
at  autopsy  appear  as  whitish  cords.  In  one  case  more  than 
one-fourth  volume  was  obtained  by  ether  extraction  from 
the  blood.74  Sometimes  the  fat  is  present  in  practically 
normal  amount,  but  the  Cholesterin  and  lecithin  are  much 
increased.75  Upon  what  the  lipsemia  essentially  depends, 
it  is  impossible  to  say.  The  fact  that  it  frequently  parallels 
the  acidosis,  and  becomes  especially  marked  in  the  coma, 
strongly  suggests  a  connection  with  tissue  disintegration, 
especially  some  process  which  sets  free  the  fat.  At  one 
time  a  reduction  of  the  lipolytic  power  of  the  blood  was  sup- 
posed to  be  an  important  factor.  In  recent  times,  however, 
our  views  have  changed  essentially  in  that  (as  will  be  dis- 
cussed more  fully  hereafter)  it  has  been  recognized  that  the 
supposed  destruction  of  fat  in  the  blood  is  really  a  masking 
of  the  fat.  We  are  likely,  too,  to  view  with  a  proper  hesi- 
tancy statements  to  the  effect  that  diabetic  blood  containing 
excessive  fat  shows  a  loss  in  the  fat  when  mixed  with  normal 
blood.    We  did  not  in  those  earlier  days  clearly  understand 

12 Literature  upon  Diabetic  Lipsemia:  C.  v.  Noorden,  Handb.  d.  Patbol. 
d.  Stoffwechs.,  2d  ed.,  2,  102-104,  135,  1907. 

73  E.  Neisser  and  E.  Derlin,  Zeitschr.  f.  klin.  Med.,  51.  428,  1904. 

'*C.  Frugoni  and  G.  Marcbetti  (Florence),  Berlin,  klin.  Wocbenschr.,  1908? 
1844. 

76  G.  Klemperer  and  H.  Umber,  Zeitschr.  f.  klin.  Med.,  61,  145,  1907. 


SUBSTITUTES  FOR  BREAD  FOR  DIABETICS        271 

the  importance  of  the  great  changes  which  physical-chemical 
adsorption  is  likely  to  induce  in  colloidal  systems. 

Respiration  Experiments  in  Diabetes. — Reference  has  al- 
ready been  made  to  the  fact  that  we  cannot  seriously  attri- 
bute any  general  reduction  of  oxidation  processes  to  the 
diabetic  organism.  Numerous  respiration  experiments,  first 
by  Pettenkofer  and  Voit  and  later  by  other  investigators,76 
have  shown  in  diabetics  either  normal  ratios  or  in  some 
instances  a  notable  increase  in  the  utilization  of  oxygen,77 
just  as  has  been  noted  in  case  of  animals  with  pancreatic 
diabetes  and  supposedly  due  to  stimulations  caused  by  the 
sugar  and  acetone  bodies.78 

The  hypothesis  of  Falta 79  that  diabetes  is  due  to  some 
disturbance  in  the  equilibrium  between  the  internal  secre- 
tory glands  (pancreas,  the  chromaffine  system,  the  thyroid 
and  parathyroids)  which  are  presumed  to  regulate  the 
metabolism  of  carbohydrate  material,  will  be  reverted  to 
later. 

Of  course  it  is  impossile  here  to  take  up  fully  the  matter 
of  dietetic  treatment  of  diabetes,  desirable  and  important 
as  it  is  for  the  practitioner ;  at  best  it  must  suffice  to  briefly 
refer  to  a  few  points  of  special  biochemical  interest. 

Substitutes  for  Bread  for  Diabetics. — The  fact  that  lsevu- 
lose  is  invariably  assimilated  with  more  readiness  by  the 
diabetic  economy  than  dextrose  has  led  to  the  employment  of 
its  polysaccharide,  inulin  (which  occurs  in  Jerusalem  arti- 
choke meal,  black  salsify  and  artichokes)  as  an  article  of  diet 
for  diabetics.  Experiments  in  ISTaunyn's  clinic  have,  how- 
ever, indicated  that  while  occasional  use  of  this  sugar  or  its 
polysaccharide  is  well  tolerated,  the  toleration  soon  de- 

76  Leo,  Katzenstein,  Weintraud  and  Laves,  Magnus-Levy,  Mohr.  Litera- 
ture: A.  Jaquet,  Ergebn.  d.  Physiol.,  2',  555-556,  1903;  Umber,  Lehrb.  d. 
Ernähr.,  p.  171,  1909. 

77  Cf.  the  experiments  of  W.  Falta  (with  Benedict),  conducted  with  the 
respiration  calorimeter  in  Boston:    Wiener  klin.  Wochenechr.,  22,  565,  1909. 

78 A.  Leimdörfer    (v.  Noorden's  Clinic),  Biochem.  Zeitschr.,  40,  326,  1912. 

78  W.  Falta  (v.  Noorden's  Clinic),  Zeitschr.  f.  klin.  Med.,  66,  5-6,  1908. 


272  HUMAN  DIABETES 

creases  in  continued  ingestion,  in  consequence  of  which  little 
can  be  promised  for  these  types  of  carbohydrate  as  a  dia- 
betic food.80  Nevertheless  "inulin  treatment"  has  recently 
been  strongly  recommended  again.81 

The  desirability  of  discovering  some  form  of  harmless 
carbohydrate  for  diabetics  has  led  to  many  experiments  in 
this  line.82  Thus  it  is  said  that  a  hemicellulose  preparation 
made  from  agar-agar,  which  yields  principally  galactose  on 
hydrolysis,  has  proved  useful  in  continuous  administration 
of  diabetics,83  although  galactose  occasions  an  increase  of 
dextrose  in  the  urine  in  diabetic  animals.84  From  Iceland 
moss,  which  contains  dextrine-like  substances,  hemicelluloses 
and  pentosans,  after  modifying  its  bitter  materials  by  mix- 
ing with  proteins,  a  bread  has  been  baked.85  Aleuronat  bread 
has  been  used  as  a  carbohydrate-poor  bread-substitute;  it 
is  prepared  from  a  mixture  of  ordinary  flour  with  aleuronat 
meal  which  is  rich  in  protein  but  poor  in  carbohydrate. 

Oat-Treatments. — C.  v.  Noorden's  observation  as  to  the 
influence  of  "oat-meal  teatment"  in  diabetes  is  interesting 
and  of  practical  importance.  The  method  presents  the 
superficial  paradox  that  many  severe  cases  of  diabetes  pass 
less  sugar  in  the  urine  when  given  considerable  amounts  of 
oat-meal  than  when  kept  on  the  strictest  diet.86  Most 
authors  who  have  tried  von  Noorden's  suggestion  have  been 
forced  to  acknowledge  that  the  treatment  in  certain  cases 
is  followed  by  a  diminution  of  the  glycosuria  and  acidosis 
and  by  an  increased  tolerance  for  carbohydrates.87     It  is 

60  Cf.  F.  Umber,  Lehrb.  der  Ernähr.,  p.  201,  1909. 

81  H.  Strauss  (Berlin),  Berl.  klin.  Wochenschr.,  1912,  1912. 

82  Cf.  A.  Magnus-Levy,  Berl.  klin.  Wochenschr.,  1910,  233. 

83  A.  Schmidt  and  H.  Lohrisch  (Halle),  Deutsch,  med.  Wochenschr.,  1908, 
2012. 

84  W.  Brasch,  Zeitschr.  f.  Biol.,  50,  113,  1908. 

85  E.  Poulsson,  Festschr.  f .  O.  Hammersten,  Wiesbaden,  1906 ;  cited  in 
Centralbl.  f.  Physiol.,  21,  196,  1907. 

88  C.  v.  Noorden,  Berlin  klin.  Wochenschr.,  1903,  817. 

87  Cf.  Literature:  C.  v.  Noorden,  Handb.  d.  Pathol,  d.  S^offwechs.,  2d  ed., 
2,  63,  1907,  and  F.  Umber,  Lehrb.  d.  Ernähr.,  pp.  208-210,  1909;  Klotz  (Strass- 
burg),  Zeitschr.  f.  exper.  Pathol.,  8,  601,  1911. 


MEDICINAL  TREATMENT  273 

not  known  how  to  explain  this  remarkable  influence.  By 
some  it  is  said  that  the  oatmeal  shows  its  full  specific  influ- 
ence only  when  used  in  whole  form,  the  individual  con- 
stituents failing  of  effect.88  Others  89  hold  that  experiments 
with  isolated  oat-starch  give  practically  the  same  favorable 
results  as  does  ordinary  oat-meal  diet.  Oat-starch,  if  this 
be  true,  is  different  from  other  starches  in  its  behavior  in 
the  diabetic  economy. 

Influence  of  Mineral  Waters. — It  is  generally  known  that 
the  use  of  certain  mineral  spring  waters  has  long  played 
a  large  role  in  the  treatment  of  diabetes.  ' '  The  real  factors 
in  the  undoubtedly  favorable  influence  of  residence  in  estab- 
lishments at  Carlsbad,  Neuenahr,  etc.,  upon  certain  forms 
of  diabetes,"  remarks  F.  Umber  90  in  his  excellent  book,  full 
of  the  spirit  of  the  wholesome  critic,  "are  certainly  not  due 
to  the  effects  of  the  waters  themselves,  but  to  other  condi- 
tions, as  the  rest,  the  well-regulated  mode  of  living,  change 
of  surroundings  and,  by  no  means  the  last,  to  physicians 
especially  experienced  in  this  field  of  pathology.  The  dia- 
betic subjects  who  are  most  benefited  on  the  spot  from 
this  sort  of  treatment  are  those  belonging  in  the  milder 
type  of  the  disease,  possibly  afflicted  by  disturbances  of  the 
liver,  the  digestive  organs,  etc.,  upon  which  as  experience 
shows  the  methods  of  treatment  at  the  baths  have  an  espe- 
cially good  influence.  These  people  are  likely  to  be  par- 
ticularly benefited  at  such  cures  if  they  are  not  in  position, 
for  special  professional  or  other  reasons,  to  live  a  properly 
regulated  life  at  home. ' ' 

Medicinal  Treatment  of  Diabetes. — Naunyn  is  disposed 
to  pass  a  practically  quashing  judgment  upon  the  medicinal 
therapy  of  diabetes,  characterizing  the  whole  numberless 

88 O.  Baumgarten  and  G.  Grund  (Halle,  a.  S.),  Deutsch.  Arch.  f.  klin.  Med., 
10k,  168,  1911. 

88  A.  Magnus-Levy,  Verhandl.  d.  28.  Kongr.  f.  innere  Med.,  Wiesbaden, 
p.  246,  1911;    cf.  also  discussion  ensuing. 

90  F.  Umber,  Lehrb.  d.  Ernähr.,  usw.,  p.  236,  1909. 
18 


274  HUMAN  DIABETES 

group  of  remedies  which  have  been  used  and  lauded,  as 
untrustworthy  or  ineffective  (with  the  exception  of  opium). 
It  is  not  known  which  of  the  alkaloids  of  opium  is  responsible 
for  the  influence  clearly  manifested  in  many  cases  by  the 
drug  in  lowering  glycosuria.  One  can  scarcely  expect  that 
as  long  as  the  real  nature  of  diabetes  is  not  thoroughly 
appreciated  any  particularly  brilliant  result  will  be  attained 
by  an  essentially  desultory  prying  around  with  physiologi- 
cally different  or  even  indifferent  substances. 


CHAPTER  XII 

PHLORIDZIN  DIABETES.    L^EVULOSURIA.    LACTOSURIA. 

PENTOSURIA.     EXPERIMENTAL  GLYCOSURIAS  OF 

DIFFERENT  KINDS 

PHLORIDZIN  DIABETES 

Having  familiarized  ourselves  in  the  last  lecture  with 
the  general  nature  of  pancreatic  diabetes,  our  attention  may 
be  devoted  to  other  physiologically  important  forms  of 
glycosuria,  of  which  phloridzin  diabetes  is  the  first  to  be 
taken  up  for  consideration. 

As  is  well  known  we  are  indebted  to  J.  von  Mering  for 
the  discovery  that  a  glucoside  found  in  the  roots  of  apple-, 
pear-  and  cherry-trees,  known  as  phloridzin,  when  given  to 
human  beings  or  to  animals,  is  capable  of  causing  a  notable 
excretion  of  sugar.  On  hydrolysis  phloridzin  splits  into 
glucose  and  phloretin,  the  latter  substance  also  manifesting 
diabetogenous  properties.  If  the  phloridzin  be  given  regu- 
larly at  intervals  of  a,  few  hours,  a  persistent  "  phloridzin 
diabetes"  will  result,  as  pointed  out  by  M.  Cremer  and  by 
Graham  Lusk.1 

Absence  of  Hyperglycemia. — It  was  soon  recognized  that 
phloridzin  diabetes  differs  essentially  from  pancreatic 
diabetes,  and  fails  to  show  one  of  the  principal  character- 
istics of  the  latter,  as  well  as  of  most  of  the  other  forms 
of  glycosuria,  namely,  hyperglycemia.  The  amount  of 
sugar  in  the  blood,  as  proved  by  numerous  investigators,  is 
not  only  not  increased  in  phloridzin  diabetes,  but  on  the  con- 
trary is  often  diminished.2  "While  in  pancreatic  diabetes 
after  removal  of  the  kidneys  or  ligation  of  the  ureters  large 

literature  upon  Phloridzin  Diabetes:  M.  Cremer,  Ergebn.  d.  Physiol., 
1',  883-886,  1902;  K.  Glässner,  Centralbl.  f.  Stoffwechselkr.,  1,  673-705,  1906; 
F.  Umber,  Lehrb.  d.  Ernährung,  pp.  143-146,  1909;  A.  Magnus-Levy,  Handb. 
d.  Biochem.,  4',  366-368,  1909;  Graham  Lusk,  Ernährung  u.  Stoffwechsel  (Ger- 
man translation  by  L.  Hess),  p.  247,  et  seq.,  1910. 

2Cf.  P.  Junkersdorf  (Bonn),  Pfiuger's  Arch.,  136,  306,  1909;  A.  Erlandsen 
(Lund),  Biochem.  Zeitschr.,  23,  329,  1910;    2k,  1,  1910. 

275 


276  PHLORTDZIN  DIABETES 

amounts  of  sugar  accumulate  in  the  blood,  here  one  cannot 
find  evidence  of  any  sugar  stagnation.  The  explanation  of 
this  peculiarity  is  simply  that  the  kidney  is  concerned  here, 
not  merely  with  the  excretion  of  the  sugar  that  is  brought 
to  it,  but  that  in  phloridzin  diabetes  the  latter  is,  at  least  in 
large  part,  produced  in  the  kidney  itself.  Here,  therefore, 
we  are  dealing  with  a  "renal  diabetes." 

Role  of  the  Kidney. — There  can  be  no  doubt  as  to  the 
essential  part  played  by  the  kidneys  in  phloridzin  diabetes. 
This  was  impressed  long  ago  by  the  experiment  of  N.  Zuntz, 
who  noted  when  he  injected  the  glucoside  into  one  of  the 
renal  arteries  that  the  corresponding  kidney  eliminated 
sugar  earlier  and  more  freely  than  its  fellow.3  In  the  same 
line  are  to  be  classed  the  perfusion  experiments  upon  ex- 
cised living  kidneys  conducted  by  Biedl  and  Kolisch 4  and 
by  Pavy 5  and  his  collaborators.  Exactly  what  is  the  renal 
activity  in  phloridzin  diabetes?  Wohlgemuth  believes  we 
are  justified  in  concluding  there  is  an  increase  of  diastases 
in  the  kidneys,  produced  from  the  influence  of  the  phloridzin, 
leading  to  an  increased  enzymic  activity  of  the  renal  cells.6 
Otto  Löwi 7  was  able  to  show,  contrary  to  opposite  opinions,8 
that  sugar  elimination  by  a  phloridzin  kidney  is  not  in- 
creased by  setting  up  in  addition  a  salt  diuresis.  There  is, 
therefore,  an  increased  activity  of  a  special  kind  seen  in 
the  effect  of  phloridzin. 

Many  writers  were  disposed  to  interpret  phloridzin  dia- 
betes on  the  assumption  that  normally  the  blood  sugar  is 
retained  by  the  kidneys  because  it  is  not  in  a  free  state  but 
in  colloid  combination ;  that  in  phloridzin  diabetes  this  com- 


3  N.  Zuntz,  Verh.  d.  Berlin.  Physiol.  Ges.,  Arch.  f.  Anat.  u.  Physiol.,  1895, 
570. 

*A.  Biedl  and  Kolisch,  Verh.  d.  18.  Kongr.  f.  innere  Med.,  p.  573,  1900. 

8F.  W.  Pavy,  T.  G.  Brodie  and  R.  L.  Siau  (London),  Jour,  of  Physiol.,  29, 
467,  1903. 

6  J.  Wohlgemuth,  and  J.  Benzur,  Biochem.  Zeitschr.,  21,  460,  1909. 

'Otto  Löwi  and  E.  Neuhauer  (Pharm.  Instit.,  Vienna),  Arch.  f.  exper. 
Pathol.,  59,  57,  1908. 

8  S.Weber  (Minkowski's  Clinic)  ,  Arch.  f.  exper.  Pathol.,  54,  1,  1905. 


FORMATION  OF  SUGAR  IN  THE  KIDNEY  277 

bination  is  broken  in  the  kidneys  and  these  organs  are  then 
enabled  to  niter  the  sugar  out  of  the  blood.  Under  the  in- 
fluence of  phloridzin  very  considerable  quantities  of  sugar 
may  appear  in  the  urine,  to  be  invariably  made  good  at 
expense  of  the  proteins  after  consumption  of  the  carbohy- 
drate supply  of  the  body.  Possibly  this  may  be  explained 
by  the  idea  that  (very  much  as  a  Toricellian  vacuum  has  a 
tendency  to  attract  gases)  the  body  does  not  permit  the 
existence  of  a  "sugar  vacuum"  in  the  blood  but  endeavors 
to  repair  the  void  with  all  the  substances  at  its  command. 
But  in  criticism  of  this  attempt  to  explain  the  nature  of 
phloridzin  diabetes  it  must  be  recalled  that,  as  has  been 
previously  discussed,  we  have  no  certain  ground  for  predi- 
cating the  existence  of  such  a  colloidal  combination  of  the 
sugar  in  the  blood. 

There  is  no  reason  for  supposing  this  form  of  diabetes 
to  be  in  any  way  related  with  the  glycogen  function  of  the 
liver.  Frank  and  Isaak9  were  able  to  show  that  dogs  in 
state  of  starvation  continue  to  eliminate  large  amounts  of 
sugar  when  jDhloridzin  is  administered  even  after  inhibition 
of  the  hepatic  function  (that  is,  after  severe  changes  have 
been  produced)  by  phosphorus  poisoning. 

Formation  of  Sugar  in  the  Kidney. — These  last  authors 
have,  in  the  writer's  opinion,  made  a  suggestion  worth  con- 
sidering, that  the  kidney  under  the  influence  of  phloridzin 
is  not  only  able  to  separate  sugar  from  the  blood,  but  be- 
comes capable  of  inducing  synthesis  of  sugar  and  acquires 
the  property  of  building  up  sugar  from  non-carbohydrate 
primary  material.  The  observation  that  in  animals  with 
phloridzin  diabetes  there  usually  is  to  be  found  an  increased 
quantity  of  sugar  in  the  blood  after  some  days  of  well 
marked  hypoglycemia  is  explained  on  the  supposition  that 
the  blood  becomes  charged  with  sugar  from  the  kidneys. 

9  E.  Frank  and  S.  Isaak,  Verh.  d.  17.  Kongr.  f.  internal.  Med.,  Wiesbaden, 
1910,  p.  586;    Arch.  f.  exper.  Pathol.,  6If,  274,  293,  1911. 

10  R.  Lepine,  C.  R.  Soc.  de  Biol.,  68,  448,  1910. 


278  PHLORIDZIN  DIABETES 

Leprae's  10  discovery  that  in  phloridzin  poisoning  the  blood 
of  the  renal  vein  contains  more  sugar  than  that  of  the  renal 
artery  may  be  regarded  as  in  the  same  line.  Asher,11  after 
stimulating  the  chorda  tynrpani  found  such  a  marked  in- 
crease of  sugar  in  the  blood  passing  from  the  submaxillary 
salivary  gland  that  it  must  necessarily  be  assumed  that  under 
irritation  sugar  passes  out  of  the  glandular  cells  into  the 
blood.  It  may  be  conceived  that  in  an  analogous  manner  the 
kidney  under  the  stimulus  of  phloridzin  becomes  able  to  give 
off  an  excess  of  sugar  to  the  blood.  Frank  and  Isaak,  how- 
ever, would  explain  the  essential  character  of  phloridzin 
diabetes  as  consisting  of  an  acquired  inability  on  the  part  of 
the  kidneys  to  fix  the  glucose  brought  to  them  by  the  blood 
and  utilize  it  in  their  own  metabolism,  and  as  a  consequence 
becoming  permeable  to  the  sugar  and  excreting  it.  Just 
as  the  liver  in  pancreatic  diabetes — and  with  the  very  same 
failure — the  kidney  attempts  to  make  good  the  loss  by  con- 
tinuous reformation.  The  question  whether  the  phloridzin 
kidney  really  acquires  the  ability  to  produce  sugar  de  novo 
is  one  which  apparently  should  receive  further  study. 

The  hypothesis  that  the  influence  of  phloridzin  is  pro- 
ductive of  "a  general  glandular  diabetes  with  predominant 
involvement  of  the  kidneys"  and  of  a  disturbance  of  the 
vital  sugar  fixation  12  finds  some  support  in  the  fact  that, 
as  proved  upon  a  dog  with  a  biliary  fistula,  after  injection 
of  phloridzin  sugar  is  to  be  found  not  only  in  the  urine 
but  also  in  the  bile.13  No  constant  direct  influence  from 
phloridzin  upon  the  formation  of  glycogen  in  the  liver  has 
been  successfully  proved  by  perfusion  experiments.14  It 
may,  therefore,  be  conjectured  that  the  sugar  elimination  in 
phloridzin  diabetes  results  from  activity  of  the  glandular 
epithelium  in  much  the  same  way  as  milk  sugar  is  produced 

u  L.  Asher  and  Karaulow,  Biochem.  Zeitschr.,  25,  36,  1910. 
u  E.  Frank  and  S.  Isaak,  Arch.  f.  exper.  Pathol.,  64,  326,  1910. 
UR.  T.  Woodyatt  (Chicago),  Jour,  of  Biol.  Chem.,  7,  133,  1910. 
14  B.  S.  Schöndorff  and  F.  S'uckrow  (Bonn) ,  Pfliiger's  Arch.,  138,  538,  1911; 
opposed  view,  K.  Grube,  ibid.,  128,  1909,  and  139,  1911. 


FORMATION  OF  SUGAR  IN  KIDNEY  279 

in  the  mammary  glands.  It  is  interesting  to  note,  too,  that 
phloridzin  has  been  found  by  observations  on  milk  cows  to 
increase  the  amount  of  sugar  in  milk,15  which  may,  how- 
ever, perhaps  be  due  to  a  relative  inspissation  of  the  milk 
from  the  effect  of  the  increased  diuresis.16  Significantly, 
Underhill  has  been  able  to  show  that  hyperglycemia  will 
result  from  administration  of  phloridzin  after  excluding  the 
renal  function.17 

Numerous  investigations  have  been  made  upon  the  gen- 
eral metabolism  in  phloridzin  diabetes.  The  same  results 
have  been  obtained  in  the  ratio  between  sugar  elimination 
and  nitrogen  elimination  in  the  dog  with  phloridzin  diabetes 
as  in  the  diabetic  human  being  (D :  N  =  3.6 : 1)  in  the  studies 
of  Graham  Lusk  and  his  associates.18  It  is  worthy  of  note 
that  an  injection  of  phosphorus,  which  in  a  normal  dog  is 
followed  by  a  marked  increase  of  nitrogen  elimination,  in  the 
dog  with  phloridzin  diabetes  causes  no  greater  heightening 
of  toxic  protein  decomposition.19  The  increase  of  Creatinin 
excretion 20  and  of  elimination  of  aminoacids 21  seen  in 
phloridzin  diabetes  may  be  regarded  as  evidence  of  this 
protein  destruction. 

From  the  investigation  of  G.  Rosenfeld,  J.  Baer  and 
others  it  is  evident  that  a  disturbance  of  the  nitrogen  bal- 
ance, as  that  induced  by  starvation  or  carbohydrate-free 
diet,  occurs  in  phloridzin  diabetes  with  mobilization  of  fat 
and  acidosis.  The  former  of  these  features  manifests  itself 
as  a  fatty  infiltration  of  the  liver,  the  fat  disappearing  from 
other  parts  of  the  body  and  massing  itself  in  the  liver. 

13  Cornevin,  Compt.  Rend.,  116,  263,  1893. 

16  C.  Porcher,  Compt.  Rend.,  1S8,  1475,  1908. 

17  F.  P.  Underhill  (Yale  Univ.,  New  Haven),  Jour,  of  Biol.  Chem.,  IS,  15, 
1912. 

MG.  Lusk,  Ernährung  und  Stoffwechsel,  p.  250,  et  seq.,  1910;  cf.  also 
A.  J.  Ringer  (Univ.  of  Penna.),  Jour,  of  Biol.  Chem.,  12,  431,  1912. 

u  W.  E.  Ray,  T.  S.  McDermott  and  Graham  Lusk,  Amer.  Jour,  of  Physiol., 
S,  139,  1899. 

20  C.  G.  L.  Wolf  and  E.  Osterberg  (Cornell  Univ.,  New  York),  Amer.  Jour. 
of  Physiol.,  28,  71,  1911. 

21  J.  Yoshikawa  (Kyoto),  Zeitschr.  f.  physiol.  Chem.,  78,  475,  1911. 


280  PHLORIDZIN  DIABETES 

Fate  of Phloridzin  in  theBody. — In  reference  to  this  point 
it  has  been  shown  by  a  study  emanating  from  the  laboratory 
of  M.  Cremer 22  that  a  portion  of  the  phloridzin  is  excreted 
in  the  form  of  a  combined  glycuronic  acid.  Another  part 
apparently  undergoes  further  change;  after  subcutaneous 
injection  (according  to  investigation  by  K.  Glässner  and 
E.  P.  Pick)  phloridzin  can  always  be  found  for  some  time 
in  the  blood  and  tissues  of  the  experiment  animal.  In 
nephrectomized  animals,  however,  after  small  doses  the 
glucoside  disappears,  which  perhaps  may  be  interpreted  by 
supposing  that  this  foreign  substance  is  destroyed  with  in- 
creased readiness  in  the  body  if  its  normal  elimination  is 
prevented.23  The  real  situation  of  affairs  is,  however,  not 
clear. 

Little  is  known  of  the  finer  mechanism  of  this  remark- 
able metabolic  influence  of  phloridzin.  Offhand  it  is  diffi- 
cult to  decide  whether  Biircker's  24  observation  that  phlorid- 
zin inhibits  spontaneous  oxidation  of  glucose  in  alkali 
solution,  has  anything  to  do  with  its  effect  in  producing 
diabetes.  It  is  worth  noting,  even  if  one  cannot  readily 
understand  them,  that  experiments  in  Salkowski's  labora- 
tory have  shown  that  aliphatic  alcohols  with  an  odd  number 
of  carbohydrate  atoms  in  the  molecule  (methyl  alcohol, 
propyl  alcohol,  amyl  alcohol,  glycerol),  but  not  those  with  an 
even  number  (as  ethyl  alcohol  and  butyl  alcohol)  give  rise  to 
an  increase  of  sugar  excretion  in  phoridzin  animals.25  Per- 
haps this  may  prove  a  loop  hole  through  which  we  may 
approach  a  little  nearer  the  secret  of  sugar  synthesis  in  the 
phloridzin  kidney. 

22  J.  Schiiller  (Lab.  of  M.  Cremer,  Cologne),  Zeitschr.  f.  Biol.,  56,  274,  1911. 

23 K.  Glässner  and  E.  P.  Pick  (R.  Paltauf's  Lab.),  Hofmeister's  Beitr.,  10, 
473,  1907;  Pflüger's  Arch.,  133,  82,  1910;  J.  Schiiller,  1.  c,  p.  290;  cf.  also 
opposed  view  of  E.  Leschke,  Arch.  f.  Anat.  u.  Physiol.,  1910,  437;  Pfliiger's 
Arch.,  132,  319,  1910;    135,  171,  1910. 

^Bürcker  (Tübingen),  Deutsch.  Physiol.  Kongr.,  München,  1911,  Centralbl. 
f.  Physiol.,  25,  1091,  1911. 

26  P.  Höckendorf  (Pathol.  Instit.,  Chem.  Div.,  Berlin),  Biochem.  Zeitschr., 
23,  281,  1909. 


DETECTION  OF  LiEVULOSE  281 

The  capacity  of  glutaric  acid  to  inhibit  the  glycosuria  of 
phloridzin  intoxication,  discovered  by  E.  Baer  and  Blum, 
must  probably  be  regarded  as  in  some  way  connected  with 
an  influence  of  the  former  upon  the  kidneys.20 

Having  discussed  the  nature  of  the  two  most  important, 
and  as  it  were  classical  forms  of  experimental  glycosuria, 
pancreatic  diabetes  and  phloridzin  diabetes,  as  far  as  is 
here  possible  and  as  far  as  the  present  status  of  our  knowl- 
edge permits,  our  attention  may  next  be  given  to  several 
atypical  forms  of  glycosuria,  namely,  Icevulosuria,  pento- 
suria and  lactosuria. 

LiEVULOSURIA 

The  literature  devoted  to  laevulosuria,  as  may  be  seen 
in  the  comprehensive  articles  upon  the  subject  by  Neuberg,27 
Magnus-  Levy 28  and  Umber 29  occupies  a  considerable  space, 
— greater,  probably,  than  the  actual  importance  of  the  sub- 
ject requires.  Many  cases  in  the  older  literature,  said  to  be 
instances  of  laevulosuria  because  of  their  Polarimetrie  char- 
acteristics, should  be.  excluded  for  the  reason  that  in  their 
determination  no  care  was  taken  to  exclude  the  possibility 
that  laevogyration  might  have  been  due  to  ß-oxybutyric  acid 
or  combined  glycuronic  acids. 

Detection  of  Lcevulose. — One  should  not  be  content  in  try- 
ingtyo  determine  the  existence  of  a  hevulosuria  with  the  recog- 
nition of  disproportion  between  Polarimetrie  features,  grade 
of  reducing  and  fermentescibility  of  the  specimen,  but 
should  employ  more  direct  methods.  Seliwanoff's  test  in 
its  various  modifications,  producing  a  red  color  when  the 
specimen  is  boiled  with  resorcin  and  hydrochloric  acid,  is 
the  most  prominent.     The  red  color  changes  to  a  yellow 

49  Cf.  G.  G.  Wilenko,  Ther.  d.  Gegenw.,  1909,  227;  E.  Frank  and  S.  Isaak, 
Verhandl.  d.  27.  Kongr.  f.  inner  Med.  (Senator's  Clinic),  Wiesbaden,  1910, 
p.  590. 

21  C.  Neuberg,  Handb.  d.  Pathol,  d.  Stoffwechs.,  2d  ed.,  2,  212-219,  1907. 

28  A.  Magnus-Levy,  Handb.  d.  Biochem.,  //',  385-394,  1909. 

29  F.  Umber,  Lehrb.  d.  Ernährung,  pp.  249-253,  1909. 


282  LiEVULOSURIA 

in  acetic  ether  when  the  solution  is  alkalinized  with  soda. 
The  interpretation  of  the  result  of  this  reaction,  however, 
requires  considerable  judgment,  as  the  presence  of  nitrites 
in  the  urine  can  be  mistaken  for  the  presence  of  laevulose.30 
Other  color  reactions  are  also  employed  for  the  detection  of 
laevulose,  among  them  the  blue  coloration  resulting  from 
boiling  the  urine  with  diphenylamine  and  hydrochloric 
acid.31     According  to  Neuberg,  the  asymmetrical  methyl- 

Phenylhydrazine,  Nn— NH2 ,     forms  an  osazone  directly 

CeHs' 

only  with  laevulose  of  the  sugars  which  are  to  be  considered, 
but  with  the  isomeric  aldehyde  sugars  (glucose,  galactose, 
mannose)  it  constantly  forms  only  the  hydrazone.  Neu- 
berg 32  regards  this  as  an  available  test  (contrary  to  objec- 
tions which  have  been  raised  to  the  trustworthiness  of  the 
reaction).33 

Transformation  of  Glucose  into  Lcevulose. — In  addition 
to  the  difficulty  of  analysis  mentioned  it  is  essential,  in  order 
to  properly  appreciate  the  statements  about  laevulosuria 
in  literature,  to  keep  prominently  in  mind  the  fact  that 
glucose  and  laevulose  under  the  influence  of  hydroxyl-ions 
may  be  very  readily  transformed  one  into  the  other  both 
within  and  outside  the  animal  body.  Thus  in  an  alkaline 
diabetic  urine,  especially  after  use  of  alkaline  drinking 
waters  a  so-called  "urogenous"  laevulosuria  can  very  read- 
ily appear.34  Although  formerly  much  was  said  and  written 
about  laevulosuria  in  diabetes  under  the  name  ''mixed 
melituria,"  most  of  the  recent  investigators  agree  that  a 
true  laevulosuria,  if  it  ever  occurs,  certainly  is  of  very  great 

30  H.  Rosin,  Salkowski  Festschrift,  cited  in  Jahresber.  f.  Tierchem.,  Slf, 
917,  1904;  L.  Borchardt,  Zeitschr.  f.  physiol.  Chem.,  55,  241,  1908;  60,  411, 
1909;  H.  Malfatti  (Innsbruck),  ibid.,  58,  544,  1909;  O.  Adler  (Prague), 
Pflüger's  Arch.,  139,  93,  1910. 

31  Cf.  Literature:    A.  Jolles,  Münchener  med.  Wochenschr.,  51,  353,  1910. 
™  C.  Neuberg,  Ber.  d.  deutsch,  chem.  Ges.,  37,  4616,  1904. 

^ R.  Ofner  (Prague),  Ber.  d.  deutsch,  chem.  Ges.,  87,  3362,  1904. 
31  Cf .  H.  Königsfeld,  Zeitschr.  f .  klin.  Med.,  69,  3-4,  1909. 


ALIMENTARY  LtEVULOSURIA  283 

rarity.35  Contrary  statements  can  be  clearly  explained  as 
faults  of  observation.36 

Tttie  Lcevulosuria. — A  spontaneous  true  laevulosuria 
seems  to  be  a  very  rare  abnormality,  seen  beyond  question 
in  only  a  very  few  cases,  and  cannot  be  said  to  be  related 
with  diabetes.  It  may  be  influenced  by  ingestion  of  laevulose 
or  cane-sugar,  but  not  of  grape-sugar,  and  disappears  on  a 
carbohydrate  free  diet.37 

The  significance  of  presence  of  laevulose  in  the  amniotic 
fluid  and  in  the  urine  of  new-born  calves  is  unknown.38  At- 
tention has  been  called  with  propriety  to  the  possibility  that 
the  laevulose  excreted  by  the  calves  in  the  first  few  days  of 
their  lives  may  have  come  from  amniotic  fluid  which  they 
swallowed.39 

Alimentary  Lcevulosuria. — In  the  course  of  the  last  few 
years  a  number  of  observations  upon  alimentary  laevulosuria 
have  been  collected,  frequently  occurring,  as  Strauss  first 
pointed  out,  along  with  disturbances  of  the  hepatic  function. 
Thus  a  decrease  in  tolerance  for  laevulose  has  been  met  in 
cirrhosis  of  the  liver,  in  marked  biliary  stagnation,  phos- 
phorus poisoning,  and  analogous  conditions.40  The  fact 
that  an  alimentary  laevulosuria  is  a  frequent  complication  of 
pregnancy  (v.  sup.)  may  also  be  suggestive  of  a  hepatic 
functional  disturbance.  Such  functional  faults  are  in  sharp 
contrast  with  true  diabetes,  as  in  this  latter  condition,  as  has 
been  seen,  the  tolerance  for  laevulose  tends  to  be  less  dimin- 
ished than  that  for  dextrose. 

So  much  for  laevulosuria. 

M  L.  Borchardt,  1.  c. ;  O.  Adler,  1.  c. ;  H.  Malfatti,  1.  c. ;  H.  Chr.  Geelumyden 
(Christiania),  Zeitschr.  f.  klin.  Med.,  70,  287,  1910. 

36  Cf.  criticism  by  Borchardt  upon  the  work  of  W.  Voit,  Zeitschr.  f.  physiol. 
Chem.,  58,  182,  1909;   60,  411,  1909,  and  reply  thereto,  ibid.,  61,  92,  1909. 

37  Cf.  Literature:  F.  Umber,  1.  c,  pp.  250-251,  and  Magnus-Levy,  1.  c, 
p.  391. 

"L.  Langstein  and  C.  Neuberg,  Biochem.  Zeitschr.,  !t,  212,   1907. 
**A.  Magnus-Levy,  1.  c,  p.  390. 

40  Cf.  Literature  in  F.  Umber,  Salkowski  Festschr.,  1904,  and  in  H.  Hohl- 
weg (Giessen) ,  Arch.  f.  klin.  Med.,  97,  443,  1909. 


284  LACTOSURIA 

LACTOSURIA 

Another  anomaly  of  metabolism  of  some  physiological 
interest  is  lactosuria.41 

The  study  of  this  condition  began  with  a  discovery  by 
Hofmeister  in  1877  of  a  reducing  substance  in  the  urine  of 
lying-in  women  which  he  recognized  as  milk-sugar. 

Since  then  we  have  framed  fairly  clear  conceptions  of 
the  conditions  under  which  lactose  passes  into  the  urine. 
We  know  as  the  ability  to  hydrolyse  the  milk-sugar  and  to 
make  full  use  of  it  is  missing  from  the  blood  and  the  tissues 
generally,  that  lactose  thus  entering  the  circulation  paren- 
terally  is  excreted  in  the  urine,  as  above  noted.  It  is  pos- 
sible that  the  animal  economy  may  in  a  measure  acquire  the 
ability  to  split  milk-sugar  parenterally  and  utilize  it  if  re- 
peated injections  of  milk-sugar  be  given42 ;  but  at  any  rate 
this  capability  does  not  exist  in  the  normal  body. 

Lactosuria  of  Puerperal  Women. — There  is  nothing  re- 
markable in  the  fact  that  if  a  woman  in  the  Puerperium  sud- 
denly has  an  interruption  of  suckling  her  infant  and  of  thus 
eliminating  large  amounts  of  milk-sugar  in  her  milk,  the 
breasts  do  not  at  once  stop  producing  lactose.  This  pent-up 
lactose  will  eventually  be  resorbed  into  the  blood  and  thence 
naturally  pass  into  the  urine.  Lactosuria,  therefore,  often 
appears,  and  has  been  frequently  observed,  as  a  reaction 
of  the  system  to  a  sudden  weaning ;  and  may  continue  for  a 
long  time,  especially  in  good  nurses.  In  milk-cows  lacto- 
suria is  a  physiological  phenomenon.43 

Again,  lactosuria  may  occur  shortly  before  delivery,  as 
at  this  time  the  mammary  glands  are  beginning  to  assume 
their  duty  and  even  the  colostrum  contains  lactose.  C.  v. 
Noorden  and  Zuelzer  have  observed  even  in  cases  of  abor- 

41  Literature  upon  Lactosuria:  C.  Neuberg,  Handb.  d.  Pathol,  d.  Stoflfw., 
2,  238-241,  1909;  A.  Magnus-Levy,  Handb.  d.  Biochem.,  4',  378-384,  1909. 

42  Cf.  J.  S.  Leopold  and  A.  v.  Reuss  (Pediatric  Clinic,  Univ.  Vienna), 
Monatschr.  f.  Kinderheilk,  8,  1,  453,  1909. 

43  Sieg,  Arch.  f.  Tierheilkunde,  35,  114,  1909,  cited  in  Jahresber.  f.  Tierchem., 
39,  663,  1909. 


LACTOSURIA  IN  INFANTS  285 

tion,  in  which  there  could  be  no  occasion  for  colostrum  pro- 
duction normally,  that  the  system  was  distinctly  disposed 
toward  elimination  of  milk-suger  in  that,  after  administra- 
tion of  large  doses  of  dextrose,  there  did  not  occur  a  glycosu- 
ria but  a  lactosuria.  Here  the  less  readily  assimilated  carbo- 
hydrate was  forced  out  of  metabolism  by  the  more  easily 
consumed  one.  C.  v.  Noorden  interpreted  this  as  a  provi- 
sion in  the  interest  of  the  offspring  by  which  the  economy 
in  preparation  for  lactation  loses  its  power  of  destroying 
milk-sugar.44  That  the  lactose  appearing  in  the  urine  of 
nursing  individuals  has  its  origin  from  the  mammary  glands 
appears  from  observations  of  disappearance  of  the  lactose 
from  the  urine  of  lactating  guinea  pigs  if  their  mammary 
glands  are  amputated.  On  the  other  hand,  however,  ob- 
servations of  P.  Best  and  Porcher 45  are  recorded  showing 
that  removal  of  the  mammary  glands  gives  rise  to  glyco- 
suria (not  lactosuria)  in  lactating  goats.  This  observation 
(not  uncontradicted)46  was  supposed  to  indicate  that  the 
liver  is  thus  interrupted  in  furnishing  to  the  functionating 
mammary  glands  the  large  amounts  of  glucose  which  may 
be  supposed  to  be  converted  in  the  latter  into  milk-sugar. 
If  this  glucose  from  the  liver  is  transferred  into  the  circula- 
tion without  the  chance  of  its  proper  use  because  of  the 
absence  of  the  mammary  glands,  of  course  its  excretion  into 
the  urine  takes  place  to  prevent  the  impending  hypergly- 
cemia. 

Lactosuria  in  Infants. — The  lactosuria  of  infants  at  the 
breast  is  quite  a  different  affair.  It  has  been  carefully 
studied  by  Langstein  and  Steinitz,47  and  is  referred  to  a 
pathological  insufficiency  of  enzymic  milk-sugar  cleavage  in 

"  Cf.  C.  Neuberg,  1.  c,  p.  240. 

"C.  Porcher,  Compt.  Rend.,  140,  1279,  1905;  141,  73,  1905;  Arch.  Internat, 
de  Physiol.,  8,  356,  1909;    Biochem.  Zeitachr.,  23,  370,  1910. 

46  C.  Foä  (Turin),  Arch,  di  fisiol.,  8,  cited  in  Biochem.  Centralbl.,  S, 
1587,  1909;  A.  Magnus-Levy  and  L.  Zuntz,  Handb.  d.  Biochem.,  4',  382,  1909; 
B.  Moore  and  W.  H.  Parker  ( Yale  Med.  School,  New  Haven ) ,  Amer.  Jour,  of 
Physiol.,  4,  239,  1900. 

e    L.  Langstein  and  F.  Steinitz,  Hofmeister's  Beitr.,  7,  575,  190G. 


286  LACTOSURIA 

the  intestine.  It  can  be  readily  appreciated  that  the  lactose 
absorbed  without  preceding  cleavage  and  in  a  sense  a 
foreign  substance  to  the  tissues,  cannot  be  utilized  in  the 
economy  of  the  infant.  It  should  be  noted  that  C.  v.  Noor- 
den  and  Zuelzer48  have  also  encountered  appreciable 
amounts  of  lactose  in  the  urine  of  children,  not  suffering 
from  gastroenteric  affections,  in  the  first  year  of  life,  pro- 
vided about  30  grams  of  milk-sugar  be  added  to  the  food. 
A  further  possibility  is  that  of  the  lactose  which  is  split 
in  the  intestine  before  resorption  the  easily  assimilable 
glucose  is  completely  burned,  while  the  less  assimilable 
galactose  fraction  passes  undecomposed  to  the  kidneys  so 
that  in  the  urine  the  lactose  is  found  mixed  with  galactose. 
Luzatto 49  noted  after  free  administration  of  milk-sugar  to 
a  dog  under  certain  experimental  conditions  only  galactose, 
but  no  lactose,  in  the  urine. 

Alimentary  Galactosuria  in  Disturbances  of  Hepatic 
Function. — This  brings  us  to  the  much  discussed  question  of 
alimentary  galactosuria.  There  is  no  doubt  that  the 
economy  possesses  the  ability  to  transform  galactose  into 
grape-sugar.  This  is  indicated  in  the  first  place  by  the  fact 
that  galactose  is  a  possible  source  of  glycogen,  and  in  the 
second  place  by  its  quantitative  conversion  into  urinary 
sugar  in  severe  diabetes.  The  actual  availability  of 
galactose  in  the  economy  is  always  very  much  lower  than 
that  of  dextrose  and  laevulose.  This  is  particularly  notable 
in  the  Carnivora,  in  which  even  after  small  dosage  of 
galactose  this  sugar  may  appear  in  the  urine.50 

In  the  course  of  the  past  few  years  alimentary  galacto- 
suria has  frequently  attracted  the  attention  of  clinicians, 
who  have  for  a  long  time  been  seeking  for  means  of  chemical 

*s  C.  v.  Noorden,  Handb.  d.  Pathol,  d.  Stoffwechs.,  2d  ed.,  2,  56,  1907. 

49  R.  Luzatto  ( Scbmiedeberg's  Lab.,  Strassburg),  Arch.  f.  exper.  Pathol., 
52,  106,  1905. 

00 Literature  upon  Alimentary  Galactosuria:  A.  Mangus-Levy,  Handb.  d. 
Biochem.,  4',  379-381,  1909. 


DISTURBANCES  OF  HEPATIC  FUNCTION  287 

diagnosis  of  the  condition  of  the  liver  in  the  living  patient. 
From  the  studies  of  E.  Bauer,51  of  v.  Neusser's  Clinic,  which 
have  met  with  confirmation  from  numerous  sources,52  an 
alimentary  galactosuria  seems  to  always  afford  a  limited 
possibility  of  testing  the  hepatic  function.  While  a  sound 
liver  is  able  to  handle  almost  all  of  the  galactose,  when  from 
30  to  40  grams  of  this  sugar  are  administered,  in  certain 
disturbances  of  the  hepatic  function  an  appreciable  por- 
tion of  it  tends  to  appear  in  the  urine.  Acording  to  Bauer 
the  test  is  positive  in  the  various  cirrhoses  of  the  liver, 
in  catarrhal  jaundice,  in  phosphorus  poisoning,  acute  yel- 
low atrophy,  and  the  fatty  liver  of  tuberculosis;  but  in 
passive  hyperemia  of  the  liver,  in  cholelithiasis,  cancers, 
tumors,  echinococcus  disease  and  abscesses  and  in  peri- 
hepatic affections  it  is  said  to  be  negative,  as  well  as  in  all 
other  affections  in  which  the  liver  does  not  take  part.  How- 
ever, there  are  exceptions  to  this  rule.  Thus  alimentary 
galactosuria  is  found  in  occasional  cases  of  Basedow's  dis- 
ease, and  was  met  in  a  case  of  paroxysmal  tachycardia 
recently  under  observation  in  Ortner's  Clinic,  which  pre- 
sented symptoms  of  vagotonia  and  sympathicotonia.53  In 
cases  of  this  sort  the  alimentary  galactosuria  is  apparently 
associated  with  an  alimentary  glycosuria. 

Bierry  succeeded  in  inducing  experimentally  an  alimen- 
tary galactosuria  by  producing  severe  lesions  of  the  liver  in 
dogs  by  means  of  chloroform  injections.  Milk  sugar  in 
dosage  of  one  or  two  grams,  easily  utilized  by  a  normal  ani- 
mal, caused  in  animals  thus  prepared  an  elimination  of 
galactose  in  the  urine.54 

51 R.  Bauer,  Wiener  med.  Wochenschr.,  1906,  21,  2537;  Deutsche  med. 
Wochenschr.,  1908,  No.  35;  Wiener  klin.  Wochenschr.,  1912,  939-941;  cf. 
Literature  in  the  last. 

62  V.  Reuss.  Bondi  and  König,  Neugebauer,  Jehn  and  Reiss  and  others. 

83 H.  Politzer  (Ortner's  Clinic,  Vienna),  Wiener  klin.  Wochenschr.,  1912, 
1303;  cf.  also  E.  Reis3  and  W.  Jehn,  R.  Roubitschek  ( Schwenkenbecher's  Clinic, 
Frankfurt  a.  M.),  Deutsch.  Arch.  f.  klin.  Med.,  108,  187,  225,  1912. 

M  H.  Bierry,  C.  R.  Soc.  de  Biol.,  61,  204,  1906. 


288  PENTOSURIA 

PENTOSURIA 

Another  abnormality  of  carbohydrate  metabolism,  of 
rare  occurrence  it  is  true,  but  of  considerable  physiological 
interest,  is  pentosuria,55  which  was  discovered  by  Salkowski 
in  1892. 

X-xylose. — Attention  has  been  called  in  a  previous  lec- 
ture (v.  Vol.  I  of  this  series,  p.  117,  et  seq.,  Chemistry  of  the 
Tissues)  to  the  importance  of  the  pentoses  in  the  construc- 
tion of  animal  and  vegetable  tissue.  Carl  Neuberg's  fine 
researches  leave  no  doubt  that  the  sugar  which  exists  so 
widely  in  the  nucleoproteins  of  animals  is  A-xylose.  The 
discovery  of  Neuberg  and  Salkowski,  who  observed 
glycuronic  acid  pass  over  into  A-xylose  in  putrefaction, 
COOH.[CH(OH)]4.COH  -  C02  =  CH2.OH.  [CH(OH)]3. 
COH,  has  cleared  up  the  obscurity  which  previously  involved 
the  origin  of  tissue  pentoses.  One  cannot  make  any  serious 
mistake  in  supposing  that  glucose  under  certain  physio- 
logical circumstances  can  be  changed  by  oxidation  into 
glycuronic  acid  and  that  the  latter  by  having  C02  split  off 
can  be  transformed  into  tissue  pentose,  even  though  up  to 
the  present  this  series  of  changes  has  not  been  proved 
beyond  peradventure. 

Another  important  connection  which  the  pentoses  have 
with  the  processes  of  animal  metabolism  is  seen  in  the  fact 
that  pentosans,  the  primary  substances  of  the  pentoses, 
occur  widely  in  the  vegetable  kingdom.  What  their  part  is 
in  the  nutrition  of  herbivora  can  be  easily  appreciated  if 
one  considers  that  many  types  of  forage  contain  twenty-five 
per  cent,  or  more  of  pentosans.  Although  there  is  but  little 
probability  that  the  pentoses  are  directly  changed  into 
glucose,  that  is  to  say,  into  glycogen  (vide  supra,  p.  230), 
and  that  this  is  conceivable  only  when  aided  by  complicated 

60  Literature  upon  Pentosuria:  C.  Neuberg,  Ergebn.  d.  Physiol.,  3',  405-410, 
1904,  and  v.  Noorden's  Handb.  d.  Pathol,  d.  Stoffwechs.,  2d  ed.,  2,  219-224,  1907; 
A.  Magnus-Levy,  Handb.  d.  Biochem.,  Jt'  395-406,  1909;  F.  Umber,  Lehrb.  d. 
Ernähr.,  pp.  242-248,  1909. 


PENTOSURIA  IN  DIABETES  289 

synthetical  processes,  it  is  also  not  very  probable  a  priori 
that  the  pentoses  are  destroyed  (as  by  fermentation  in  the 
intestine)  to  such  an  extent  as  to  be  entirely  lost  as  sources 
of  energy  for  the  body.56  While  herbivora  are  able  to  con- 
sume considerable  quantities  of  pentoses,  the  human  assim- 
ilation limit  for  these  sugars  (although  man  always  destroys 
in  his  economy  at  least  a  part  of  any  large  amounts  which 
have  been  ingested)  is  strikingly  low;  so  much  so,  in  fact, 
that  even  after  ingestion  of  a  single  gram  or  a  fraction  of  a 
gram  of  xylose,  arabinose,  rhamnose,  etc.,  the  pentose 
reactions  may  become  positive  in  the  urine. 

Alimentary  Pentosuria. — There  is  no  wonder,  therefore, 
that  an  alimentary  pentosuria  of  low  grade  (as  indicated  by 
the  studies  of  P.  Blumenthal  and  others),  particularly  after 
indulgence  in  fruits  (cherries,  plums,  apples)  and  other 
vegetable  materials,  is  met  with  appreciable  frequency. 

Pentosuria  in  Diabetes. — It  should  also  be  easy  to  under- 
stand why  a  small  amount  of  a  pentose  may  be  found  mixed 
with  the  glucose  in  the  urine  of  severe  cases  of  human 
diabetes  and  of  the  dog  in  pancreatic  diabetes,  as  was  proved 
by  E.  Kiilz  and  J.  Vogel.  The  nature  of  this  sugar  with 
five  carbon  atoms  is  apparently  not  well  known,  and  in  fact 
its  optical  activity  never  seems  to  have  been  tested.57  One 
would  probably  not  be  far  wrong  in  supposing  that  a  portion 
of  the  tissue  pentoses,  which  are  set  free  from  the  nucleo- 
proteins  in  the  breaking  down  of  the  tissues,  can  make  their 
appearance  in  the  urine.  This  idea  is  not  contradicted  by 
the  fact  that  it  is  not  possible  to  recognize  by  analysis  a 
pentose  impoverishment  of  the  tissues  in  connection  with 
pancreatic  diabetes  and  phloridzin  diabetes  in  animals.58 

56  Literature  upon  Pentosans  as  Foods :  A.  Magnus-Levy,  1.  c,  pp.  396-398. 

OTC.  Neuberg,  Handb.  d.  Pathol,  d.  Stoffwechs.,  2d  ed.,  2,  223,  1907;  cf. 
also  W.  Voit  ( Sandmeyer's  Sanatorium),  Zeitschr.  f.  physiol.  u.  diät.  Ther., 
12,  659,  1909. 

KS.  Mancini  (Siena),  Arch,  di  Farmakol.,  5,  309,  1906,  cited  in  Centralbl. 
f.  Physiol.,  20,  642,  1906;  cf.  also  L.  Caminotti,  Biochem.  Zeitschr.,  22,  106, 
1909. 

19 


290  PENTOSURIA 

Chronic  Pentosuria. — The  idiopathic  form  of  pentosuria 
is  a  complete  puzzle  to  us. 

This  is  a  comparatively  uncommon  anomaly  of  metab- 
olism. Some  twenty  cases  were  collected  a  few  years  ago 
from  the  general  literature.  Some  of  the  cases  were  neuro- 
pathic individuals,  cocaine  and  morphine  habitues ;  in  some 
a  family  disposition  was  recognized.  The  abnormality  does 
not  give  rise  to  any  special  clinical  symptoms.  Carl  Neu- 
berg, to  whom  we  owe  much  valuable  progress  in  the  chem- 
istry and  physiology  of  the  carbohydrates,  found  that  the 
sugar  eliminated  by  the  case  of  chronic  pentosuria  which  he 
studied  was  directly  different  from  the  tissue  pentose, 
A-xylose,  and  was  really  an  inactive  arabinose.  "It  is  a 
recognized  fact,"  says  Neuberg,59  "that  all  sorts  of  living 
beings  produce  optically  active  forms  exclusively,  and  acti- 
vate racemic  types  offered  to  them  by  consuming  one  of  the 
components.  The  example  of  inactive  urinary  pentose  is 
the  first  instance  of  the  occurrence  of  a  racemic  body  in  the 
animal  economy.  By  the  construction  of  urinary  pentose 
pentosuria  is  characterized  as  a  phenomenon  sui  generis." 
While  the  inactive  arabinose  if  introduced  into  the  body  of 
a  healthy  individual  (as  shown  by  Neuberg  and  Wohlge- 
muth) undergoes  cleavage  into  its  two  components,  one  of 
which  undergoes  decomposition,  the  other,  however, 
8-arabinose,  appearing  in  the  urine,  we  see  that  this  cleavage 
power  may  come  to  be  lost  by  the  economy  of  the  pentosuric. 
O.  af  Klercker60  comes  to  the  conclusion  from  his  own 
studies  that  in  pentosuria  the  two  complementally  isomeric 
pentoses  are  excreted  in  very  varying  proportions.  While 
they  are  sometimes,  as  in  Neuberg  's  case,  in  equal  amounts, 
the  A-component  may  in  some  instances  be  in  excess.  It  is 
not  known  from  what  source  the  arabinose  comes.  Its 
excretion,  according  to  Blumenthal  and  Bial,  is  independent 

M  C.  Neuberg,  Handb.  d.  Patbol.  d.  Stoffwechs.,  2d  ed.,  2,  221,  1907. 
00  0.  af  Klercker    (Instit.  of  Med.  Chem.,  Lund),  Deutsch.  Arch.  f.  klin. 
Med.,  108,  277,  1912. 


CHRONIC  PENTOSURIA  291 

of  the  quantity  of  pentoses  in  the  ingested  nucleoproteids. 
There  is  just  as  little  reason  to  refer  it  to  the  pentoses  in 
combination  in  the  tissue  proteins,  as  the  whole  supply  of 
pentoses  in  the  human  body  is  estimated  at  only  about  ten 
grams,  while  the  amount  of  urinary  pentose  which  may  be 
excreted  in  a  single  day  may  reach  thirty  grams  or  more. 
Ingested  xylose  in  a  pentosuric  (just  as  in  a  healthy  person) 
may  at  least  in  part  pass  into  the  urine.  There  is  no  more 
evidence  of  connection  between  pentosuria  and  the  metab- 
olism of  dextrose ;  it  is  not  influenced  by  total  withdrawal  of 
carbohydrates,  or  by  administration  of  phloridzin;  and 
glycuronic  acid  excretion  takes  place  in  normal  measure, 
according  to  Blumenthal  and  Bial,  after  administration  of 
chloral  or  menthol.  There  is  nothing  left  except  to  conclude 
that  the  pentosuric  individual  synthesizes  his  urinary  pen- 
tose; where,  how,  or  why,  we  do  not  know.  Neuberg  has 
suggested  a  possible  connection  between  galactose  and 
arabinose  on  the  basis  of  their  stereochemical  molecular 
configuration : 

«-GALACTOSE  a-ARABINOSE 

C.OH  COH 

H.C.OH  H.C.OH 

!  I 

OH.C.H  OH.C.H 

OH.C.H  OH.C.H. 

I  I 

H.C.OH  CH2.OH 

I 
CH2.OH 

Finally,  Luzzatto  61  has  shown  in  a  case  of  pentosuria  that 
even  the  exhibition  of  large  quantities  of  glucose,  cane-sugar 
or  starch  is  incapable  of  modifying  it  in  any  way.  If,  how- 
ever, galactose  be  given,  it  is  in  greater  part  decomposed, 
but  a  small  portion  would  seem  to  be  transformed  into 
pentose  and  the  amount  of  the  five-carbon- atom  sugar  in- 

w  R.  Luzzatto  (Camerino),  Arch.  f.  exper.  Pathol.,  Schniiedeberg  Festschr., 
1908,  366. 


292  PENTOSURIA 

creased.  Confirmation  of  this  work  with  a  refined  technic 
which  will  permit  the  possibility  of  quantitative  differentia- 
tion between  pentoses  and  hexoses,  is  very  much  to  be 
desired. 

Detection  of  Pentoses. — Most  cases  of  pentosuria  are  for 
a  time  regarded  as  diabetics  and  treated  as  such ;  and  yet 
the  diagnosis  of  pentosuria  is  not  a  difficult  one.  Even  with 
Fehling's  test  an  attentive  observer  will  notice  that  the  fluid 
at  first  remains  clear  and  only  after  considerable  boiling  is 
suddenly  and  fitfully  reduced.  Neuberg  explains  this 
peculiarity  upon  the  supposition  that  pentose  may  be  in  the 
form  of  a  ureide  in  the  urine : 

CH2.OH-(CH.OH)3-COH+^^)CO=CH2.OH-(CH.OH)3-CH=NIJl2^)CO 

+H20. 

Eeduction  can  take  place  only  in  proportion  as   such  a 

ureide  is  split  by  hydrolytic  influences  and  the  aldehyde 

group  thus  set  free;   for  which  reason  it  is  probable  that 

many  statements  as  to  the  amount  of  pentose  in  urines 

are  too  low. 

With  special  attention  it  will  be  found  in  investigating 
the  urine  of  a  pentosuric  individual  that  the  reducing  sub- 
stance of  the  urine  is  neither  f  ermentescible  nor  is  it  optically 
active.  The  Phenylhydrazine  test  yields  beautiful  yellow 
osazone-needles,  the  melting  point  of  which  is,  however,  dis- 
tinctly lower  than  that  of  glucosazone.  Transformation  of 
arabinose  into  a  diphenylhydrazone  is,  according  to  Neuberg 
and  Wohlgemuth,  also  applicable  in  testing  quantitatively 
for  arabinose  in  the  presence  of  other  carbohydrates. 
Finally,  the  Tollens  tests  in  their  different  modifications,  the 
greenish-blue  color  obtained  by  heating  with  orcin  and 
hydrochloric  acid  and  the  analogous  red  color  with  phloro- 
glucin,  and  the  spectroscopic  behavior  of  the  coloring  matter 
obtained  by  shaking  with  amylalcohol,  are  very  useful,  even 
if  they  are  not  absolutely  distinctive.     Jolles  recommends 


CAMMIDGE  REACTION  293 

distillation  of  the  isolated  pentosazone  with  hydrochloric 
acid  and  subjecting  the  distillate,  containing  furfurol,  to  the 
orcin  test;  by  which  means  it  is  said  confusion  of  pentose 
with  a  hexose  or  a  combined  glycuronic  acid  may  be  pre- 
vented.62 

Cammidge  Reaction. — In  concluding  the  consideration 
of  pentosuria  the  reaction  of  Cammidge,  which  in  recent 
years  has  attracted  a  great  deal  of  attention,  may  be  briefly 
spoken  of. 

Cammidge  63  some  years  ago  announced  that  he  believed 
he  had  found  a  characteristic  urine  reaction  for  chronic  dis- 
eases of  the  pancreas.  The  substance  concerned  in  this 
reaction  could  be  obtained  by  boiling  the  urine  with  hydro- 
chloric acid,  neutralizing  with  lead  carbonate,  and  precipitat- 
ing with  alkaline  lead.  From  the  precipitate  a  solution 
can  be  obtained  by  the  decomposing  action  of  sulphuretted 
hydrogen,  yielding  the  usual  carbohydrate  reactions  and  an 
osazone  (apparently  a  pentosazone).  Cammidge,  who  dis- 
covered this  reaction  in  dogs  in  which  a  pancreatitis  had  been 
artificially  produced,  offered  for  it  what  was  probably  a 
correct  interpretation,  relating  it  with  an  excretion  of  sugars 
of  five  carbon  atoms  which  were  derived  from  the  breaking 
down  of  nucleoproteins  of  the  pancreas,  which  is  rich  in  pen- 
tose. Many  later  investigators  have  much  simplified  the 
rather  detailed  process  of  Cammidge,  at  least  to  the  end  of 
satisfactorily  demonstrating  the  presence  of  an  osazone  in 
an  apparently  sugar-free  urine  after  hydrolysis  with  hydro- 
chloric acid. 

Cammidge 's  contribution  started  up  a  perfect  flood  of 
publications,  a  detailed  review  of  which  is  perhaps  unneces- 
sary here.  Whoever  may  desire  to  do  so  may  easily  find 
articles  by  the  dozen  in  the  last  ten  years  of  the  journals 
devoting  themselves  to  the  publication  of  abstracts.     The 

02  A.  Jolles,  Biochem.  Zeitschr.,  2,  243,  1906;  Münchener  med.  Wochenschr., 
57,  353,  1910. 

63  P.  T.  Cammidge,  Proc.  Roy.  Soc,  London,  Series  B,  81,  372,  1909. 


294  PENTOSURIA 

author  has  often  wondered  what  factors  make  particularly 
for  the  interest  of  the  great  medical  public  in  a  discovery  in 
the  field  of  his  particular  specialty.  That  such  interest 
should  be  prominently  shown  for  those  points  which  may  be 
expected  to  be  of  direct  use  in  the  practice  of  medicine  is 
quite  conceivable.  But  it  is  not  so  easy  to  understand  why 
the  greatest  interest  is  so  often  not  manifested  for  new  facts 
that  are  clear  and  unambiguous  and  represent  real  advances, 
but  by  preference  is  turned  to  indefinite,  vague  and  uncertain 
features  in  which  there  is  no  trace  of  really  precise  adapta- 
tion of  chemical  and  physiological  concepts.  It  is  probably 
not  wrong  to  believe  that  it  is  due  to  the  fact  that  there  are 
many  people  who  at  heart  are  glad  to  avoid  the  rather  great 
inconveniences  which  a  regulated  course  of  chemical  study 
brings  with  it,  but  who  in  their  own  interest  and  that  of  pos- 
terity are  unwilling  to  forego  having  a  new  starlet  blaze  in 
the  firmament  of  biochemical  research.  According  to  their 
experience  these  same  people  have  an  invincible  and  instinc- 
tive preference  for  those  fields  of  investigation  in  which 
discovery  is  decidedly  more  easy  than  control  of  the  dis- 
coveries made  by  others. 

But  to  return  to  Cammidge's  reaction,  opinions  generally 
contradict  its  practical  utility  as  an  aid  in  functional  diag- 
nosis of  pancreatic  affections.  As  to  its  real  value  it  would 
seem  from  a  few  studies  of  critical  character 64  to  be  fully 
shown  to  be  neither  distinctive  nor  especially  reliable.  It 
clearly  does  not  deal  with  any  one  single  substance;  the 
presence  of  any  poly-  or  disaccharide  in  the  urine  may  by 
cleavage  give  rise  to  an  osazone-forming  atomic  group. 
Even  the  small  amounts  of  polymeric  carbohydrates  which 
exist  normally  in  the  urine,  particularly  after  a  diet  rich  in 

44  O.  Schumm  and  Hegler,  Münchener  med.  Wochenschr.,  56,  1878,  1909, 
Mitt.  a.  d.  Hamburgischen  Staatskrankenanstalten,  11,  1910,  cited  in  Centralbl. 
f.  d.  ges.  Biol.,  10,  No.  1933;  L.  Grimbert  and  R.  Bernier,  Jour,  de  Pharm,  et  de 
Chem.,  30,  529,  1909,  cited  in  Biochem.  Centralbl.,  9,  No.  1643;  J.  E.  Schmidt 
(Enderlen  Clinic,  Würzburg),  Mitt.  a.  d.  Grenzgebiete  d.  Med.  u.  Chir.,  20,  426, 
1909. 


VARIOUS  EXPERIMENTAL  GLYCOSURIAS  295 

sugar,65  may  give  a  positive  result  by  this  reaction ;  which 
may  on  the  other  hand,  however,  be  due  to  excreted  gly- 
curonic  acids  and  pentoses.  It  cannot  possibly  be  regarded, 
therefore,  as  specific  for  pancreatic  break-down,  the  more  so 
because  any  actual  nuclear  decomposition  in  the  tissues  may 
be  followed,  as  has  been  seen,  by  passage  of  pentoses  into  the 
urine.  This  aside,  of  course  the  particularly  large  amount 
of  pentoses  in  the  pancreas  (which  is  said  to  contain  five 
times  the  quantity  of  pentose  as  the  liver  and  other  glan- 
dular organs  and  about  twenty  times  more  than  do  the 
muscles)66  favors  the  passage  of  pentoses  into  the  urine  when 
this  organ  undergoes  destructive  changes.  For  this  reason 
there  is  some  value  in  examining  the  urine  for  pentoses  as  an 
aid  to  the  diagnosis  of  pancreatic  affections. 

EXPERIMENTAL  GLYCOSURIAS  OF  VARIOUS  KINDS 

The  list  of  the  recognized  examples  of  this  abnormality 
of  metabolism  is  far  from  exhausted  even  after  completing 
the  above  mentioned  types  of  sugar  excretion  in  the  urine. 
We  are  acquainted  also  with  a  large  number  of  possibilties  of 
inducing  experimental  glycosurias  by  interferences  of  many 
kinds.  A  review  of  these  may  be  considerably  facilitated  by 
dividing,  as  Pollak 67  does,  the  glycosurias  due  primarily  to 
renal  influence  from  the  glycosurias  following  hyper- 
glycemia. 

Renal  Glycosurias. — To  the  first  of  these  groups,  besides 
the  phloridzin  diabetes  already  considered,  certain  glyco- 
surias caused  by  renal  poisons  are  to  be  referred.  According 
to  Ellinger  and  Seelig  in  rabbits  in  a  certain  stage  of 
cantharides  intoxication  it  is  impossible  to  induce  a  glyco- 
suria by  adrenin  and  the  elimination  of  sugar  by  dogs  with 

65  Cf.  R.  Wilhelm,  8  internat.  Physiol.  Kongr.,  Vienna,  1910.  (There  would 
appear  to  be  a  synthesis  therein  of  mono-  to  polysaccharides,  which  pass  into 
the  urine.) 

,SG.  Grund  (Salkowski's  Lab.),  Zeitschr.  f.  physiol.  Chem.,  35,  111,  1902. 

61  L.  Pollak  (Pharmakol.  Instit.,  Vienna),  Arch.  f.  exper.  Pathol.,  61,  366, 
1909. 


296  VARIOUS  EXPERIMENTAL  GLYCOSURIAS 

pancreatic  diabetes  may  be  lowered  by  inducing  renal 
lesions.68  In  this  stage  of  the  poisoning,  according  to 
L.  Pollak,69  it  is  possible  to  call  out  a  glycosuria  by  super- 
position of  uranium  poisoning,  although  the  amount  of  sugar 
in  the  blood  is  raised  but  little  or  not  at  all  above  the  normal 
by  this  measure.  The  explanation  proposed  is  that  while 
cantharidin  restricts  the  permeability  of  the  vessels  of  the 
kidneys  for  sugar,  uranium  makes  them  abnormally 
permeable;  and  it  is  not  improbable  that  a  comparable 
causative  mechanism  obtains  in  chromium  and  bichloride 
of  mercury  glycosuria.  A  renal  glycosuria  has  also  been 
observed  occasionally  in  human  beings  with  chronic 
nephritis. 

The  long  list  of  glycosurias  which  are  accompanied  by 
hyperglycemia  includes,  according  to  L.  Pollak  (exclusive 
of  pancreatic  diabetes  which  occupies  a  special  position)  a 
number  of  glycosurias  induced  by  sympathetic  nervous  irri- 
tation. The  factors  producing  the  glycosuria  are  again  to 
be  grouped  in  two  classes:  first,  those  which  (analogous  to 
the  sugar-puncture)  occasion  irritation  of  nervous  centres 
(transmitted  by  sympathetic  fibres,  especially  the  splanch- 
nics,  to  the  liver  and  cause  the  latter  to  throw  off  its  glycogen 
deposit) ;  and  second,  those  which  (analogous  to  adrenin 
glycosuria)  cause  an  irritation  of  the  peripheral  endings  of 
the  sympathetics. 

Sugar  Puncture. — We  know  enough  about  the  essential 
nature  of  the  sugar  puncture  of  Claude  Bernard  to  under- 
stand the  parts  the  nerve  impulses  traverse  which  produce 
glycosuria  after  injury  of  the  floor  of  the  fourth  ventricle 
of  the  brain.  This  nerve  path  extends  from  the  "sugar 
centre"  to  the  cervical  cord,  thence  out  through  communi- 
cating branches  to  the  lower  cervical  and  upper  thoracic 

68 A.  Ellinger  and  A.  Seelig  (Königsberg),  Münchener  med.  Wochenschr... 
1905,  345,  449,  and  Festschr.  f.  M.  Jaffe,  p.  349,  1901. 

69  L.  Pollak  (Pharmakol.  Instit.,  Vienna),  Arch.  f.  exper.  Pathol.,  64,  415, 
1911. 


SUGAR  PUNCTURE  297 

sympathetic  ganglia,  and  thence  along  the  splanchnics  to  the 
liver.  We  know,  too,  that  stimulation  of  the  central  segment 
of  the  vagus  and  of  numerous  sensory  (particularly  visceral) 
nerves  will  induce  activity  of  the  sugar-centre,  and  that  a 
great  variety  of  anatomical  lesions  of  the  central  nervous 
system  (from  traumatism,  tumors,  abscesses,  hemorrhages, 
etc.)  may  act  in  the  same  way.  Psychic  influences  may  also 
induce  glycosuria.  For  example,  in  cats  that  have  been  shut 
up  in  a  cage  and  worried  for  half  an  hour  by  a  dog  enough 
to  have  had  the  latter  very  manifestly ' '  get  on  their  nerves, ' ' 
a  glycosuria  may  be  observed.70 

We  have  no  reason  for  doubting  that  the  mechanism  of 
the  sugar  puncture  involves  the  liver  and  includes  a  process 
of  discharging  its  glycogen  supply;  but  it  is  not  clearly 
understood  in  all  points.  Only  recently  two  French  investi- 
gators ( Wertheimer  and  Battez)  have  called  attention  to  the 
effectiveness  of  the  sugar  puncture  even  in  animals  which 
have  been  placed  under  the  influence  of  atropin  sufficiently 
to  induce  a  paralysis  of  all  secretory  nerves ;  and  they,  there- 
fore, hold  that  the  supposed  connection  of  the  sugar  puncture 
with  stimulation  of  glyco secretory  nerves  is  decidedly  ques- 
tionable.71 The  possibility  of  a  connection  between  the  su- 
gar puncture  and  the  secretory  activity  of  the  adrenals  will 
be  taken  up  fully  in  the  succeeding  lecture,  in  which  the  re- 
lation between  the ' '  internal  secretory  glands ' '  and  carbohy- 
drate metabolism  will  be  considered. 

Attention  should  also  be  called  here  to  the  occurrence  of 
glycosuria,  according  to  observations  of  Minkowski,  Bedard, 
Pflüger  and  other  authors,72  after  a  great  variety  of  opera- 
tive interferences ;  it  is  especially  likely  to  follow  irritation 
of  the  bowel  and  peritoneum,  according  to  Pflüger.  Zak 
states  that  even  the  mechanical  irritation  of  the  intestine 

70 W.  B.  Cannon,  A.  T.  Strohl  and  W.  S.  Wright  (Harvard  Med.  School), 
Amer.  Jour,  of  Physiol.,  29,  280,  1911. 

71  E.  Wertheimer  and  G.  Battez,  Arch,  internat.  de  Physiol.,  9,  140,  363, 
1910;    C.  R.  Soc.  de  Biol.,  66,  1059,  1909. 

72  Rose,  Zak,  Gaulthier,  Eichler  and  Silbergleit,  Visentini. 


298  VARIOUS  EXPERIMENTAL  GLYCOSURIAS 

occasioned  by  introducing  a  drainage  tube  may  produce  this 
effect.  Ulrich  Rose  invariably  found  a  hyperglycemia,  and 
sometimes,  too,  glycosuria,  in  rabbits  after  a  simple 
laparotomy.  And  Kreidl  and  Winkler  73  have  been  able  to 
prove  that  after  opening  the  peritoneal  cavity  in  dogs  and 
cats,  but  less  frequently  in  rabbits,  it  is  almost  a  regular 
thing  to  find  sugar  in  the  urine.  We  would  probably  not  be 
far  out  of  the  way  in  supposing  that  in  all  procedures  of  this 
sort,  comparably  with  Bernard's  puncture,  we  have  to  deal 
with  an  effect  upon  the  sympathetic  nervous  apparatus  and 
with  a  discharge  of  glycogen  from  its  place  of  storage. 

Toxic  Glycosurias. — L.  Pollak  is  disposed  to  regard  many 
forms  of  toxic  glycosuria,  as  that  in  the  course  of  caffein 
poisoning  and  strychnine  poisoning,  as  due  to  a  central 
nervous  irritation  analogous  to  that  produced  by  the  punc- 
ture. All  sorts  of  explanations  have  been  offered  for  the 
action  of  other  harmful  chemicals  like  ether,  chloroform, 
morphine,  nitrite  of  amyl  or  carbon  monoxide,  but  thus  far 
without  any  uniformity  at  all.74 

Salt  Glycosuria. — "Salt  glycosuria"  is  also  supposed  to 
be  due  to  a  direct  irritation  of  the  sugar  centre.  Injection  of 
large  amounts  of  a  dilute  (about  one  per  cent.)  solution  of 
sodium  chloride  into  the  vascular  system  of  an  animal,  is 
likely  to  occasion  a  glycosuria,  according  to  M.  H.  Fischer, 
but  fails  to  do  so  if  the  splanchnic  nerves  be  cut.  A  glyco- 
suria of  much  more  marked  intensity  can  be  induced  if  the 
salt  solution  be  introduced  directly  into  the  vertebral  artery 
of  the  experiment  animal  instead  of  into  a  vein,  thus  insuring 
a  direct  effect  upon  the  nervous  centres.  Injections  of  sea 
water,  diluted  to  the  osmotic  pressure  of  the  blood,  will  also 
give  rise  to  glycosuria.  The  glycosuria  produced  by  sodium 
chloride  can  be  inhibited  to  some  degree  by  injection  of 

78  F.  Winkler  (under  direction  of  A.  Kreidl,  Vienna),  Centralbl.  f.  Physiol., 
21t,  No.  8,  1910;    cf.  therein  Literature. 

"Literature  upon  Toxic  Glycosurias:  K.  Glässner,  Wiener  klin. 
Wochenschr.,  1909,  No.  26. 


GLYCOSURIA  FROM  CHILL  299 

potassium  and  calcium  salts.75  Injection  of  concentrated 
salt  solutions  produces  pronounced  hyperglycemia,  but  there 
is  also  induced  an  alteration  in  the  renal  efficiency  (probably 
due  to  change  of  the  osmotic  pressure  relations)  and  the 
glycosuria  may  fail  to  appear.76 

Glycosuria  from  Chill. — "Befrigeration  glycosuria" 
should  finally  be  briefly  mentioned,  observed  first  by  Böhm 
and  Hoffmann  and  later  by  Araki  when  they  reduced  the 
body  temperature  of  warm  blooded  animals  to  a  low  level  by 
cold  baths,  snow  packs,  etc.  Grlässner 77  was  in  the  same  way 
able  to  recognize  glycosuria  in  individuals  who  had  at- 
tempted suicide  by  jumping  into  cold  water.  Whether  the 
coincident  occurrence  of  lactic  acid,  which  may  be  regarded 
as  due  to  the  combined  influence  of  oxygen  impoverishment 
and  increased  muscular  activity,  has  any  direct  connection 
with  the  glycosuria,  may  remain  undecided.  Even  in  frogs 
a  glycosuria  may  be  induced  by  exposure  to  intense  cold, 
interpreted  by  M.  Löwit 78  on  the  hypothesis  that  the  oxida- 
tion processes  are  interfered  with,  and  that  as  a  result  there 
may  ensue  disturbance  in  the  consumption  of  sugar,  altera- 
tion of  the  renal  permeability  and  glycosuria. 

"  M.  H.  Fischer,  Pfltiger's  Arch.,  109,  1,  1905,  and  earlier  contributions: 
O.  H.  Brown,  Amer.  Jour,  of  Physiol.,  10,  378,  1904;  T.  C.  Burnett  (Univ.  of 
California),  Jour,  of  Biol.  Chem.,  4,  57;   5,  351,  1908. 

T6G.  Wilenko   (Lemberg),  Arch.  f.  exper.  Pathol.,  66,  143,  1911. 

"  K.  Glässner,  Wiener  klin.  Wochenschr.,  1906,  p.  30. 

78  M.  Löwit,  Arch.  f.  exper.  Pathol.,  60,  1908. 


CHAPTER  XIII 

RELATIONS  OF  GLANDS  WITH  INTERNAL  SECRE- 
TION TO  CARBOHYDRATE  METABOLISM. 
GLYCURONIC  ACIDS 

RELATION  OF  THE  ADRENALS  TO    CARBOHYDRATE 
METABOLISM 

In  the  course  of  a  series  of  earlier  lectures  the  writer 
attempted  to  present  what  is  known  of  the  role  and  the 
significance  of  "the  glands  with  internal  secretion,"  at  least 
as  far  as  the  principal  points  are  concerned.  An  important 
phase  of  this  physiological  problem  has  not,  however,  been 
systematically  dealt  with,  the  relations  these  puzzling  organs 
bear  to  carbohydrate  metabolism.  In  the  present  lecture  it 
is  proposed  to  fill  in  this  hiatus  and  to  consider  the  matter 
in  an  objective  manner,  so  that  it  may  be  possible  to  come 
to  some  conclusion  to  what  extent  we  are  justified  in  the 
effort  so  often  made  in  the  course  of  the  last  few  years  to 
penetrate  into  the  secrets  of  normal  and  pathological  car- 
bohydrate metabolism  and  to  interweave  these  with  the  no 
less  secret  and  obscure  mysteries  of  the  "ductless  glands" 
into  one  organic  whole. 

Nature  of  Adrenal  Diabetes. — The  line  of  thought  which  is 
principally  to  occupy  our  attention  in  the  present  discussion, 
takes  its  inception  from  the  discovery  of  adrenal  diabetes.1 

In  1901  F.  Blum,  in  Frankfurt,  a.  M.,  made  the  remark- 
able and  important  discovery  that  injection  of  the  substance 
in  the  adrenals  which  induces  increase  of  blood  pressure 
(known  in  the  present  stage  of  science  by  the  term  Supra- 
renin or  adrenin)  is  followed  by  an  intense  glycosuria  of 
short  duration  in  various  experiment  animals.  The  very 
great  interest  always  manifested  in  the  problem  of  diabetes 

1  Literature  upon  Adrenal  Diabetes:    A.  Biedl,  Innere  Secretion,  pp.  202- 
204,  1910;   R.  Hirsch,  Handb.  d.  Biochem.,  3,  322-325,  1910;    G.  Bayer,  Ergebn. 
d.  pathol.  Anat.,  Uh  101-105,  117-119,  1910. 
300 


NATURE  OF  ADRENAL  DIABETES  301 

from  its  clinical  and  physiological  standpoints  is  sufficiently 
explanatory  of  the  flood  of  publications  persisting  even  now 
which  had  its  beginning  in  this  discovery. 

The  glycosuric  influence  of  Suprarenin  is  appreciable  only 
when  it  is  introduced  subcutaneously,  intravenously  or  intra- 
peritoneally.    When  given  by  the  mouth  even  large  doses 
are  without  effect  upon  the  carbohydrate  metabolism  and 
the  blood  pressure.     The  glycosuria  is  directly  related  with 
the  supply  of  glycogen  in  the  liver  and  its  liquidation.     In- 
jection of  adrenin  directly  into  a  mesenteric  vein  acts,  ac- 
cording to  Doyen,  in  an  almost  paroxysmal  manner,  although 
in  dogs  with  Eck's  fistulas  it  produces  neither  hyperglycemia 
nor  glycosuria.2     Between  the  amount  of  adrenin  present 
in  the  blood  and  that  of  the  sugar  excreted  in  the  urine  there 
exists  within  certain  limits  a  direct  ratio,   according  to 
studies  made  in  Straub  's  laboratory.     The  occurence  of  a 
stage  of  latency  is  clearly  due  to  the  fact  that  a  certain 
amount  of  time  is  necessary  to  put  the  mechanism  of  sugar 
mobilization  in  motion.     Straub  believes,  as  do  others,  that 
the  parts  influenced  by  the  adrenin  are  the  same  sympa- 
thetic nerve  fibres  whose  central  irritation  is  responsible  for 
the  effectiveness  of  the  sugar  puncture.3    As  the  Supra- 
renin acts  on  the  endings  of  the  sympathetic  fibres,  one  can 
readily  appreciate  why  splanchnicotomy  does  not  prevent 
its  glycosuric  effect.4     What  actually  takes  place  is  that  the 
liver  under  the  influence  of  the  poison  passes  its  supply  of 
glycogen  into  solution;   if  this  supply  is  an  abundant  one 
(perhaps  after  preceding  indulgence  in  carbohydrates)   a 
stream  of  sugar  will  pass  out  from  the  liver  into  the  blood. 
But  if  the  store  of  glycogen  has  been  used  up  through  the 

'Michaud  (Kiel),  Verh.  d.  Kongr.  f.  innere  Med.,  Wiesbaden,  1911. 

8  W.  Straub,  Münchener  med.  Wochenschr.,  1909,  493 ;  H.  Ritzmann,  Arch, 
f.  exper.  Pathol.,  61,  231,  1909;  cf.  also  F.  P.  Underhill  and  0.  E.  Closson  (Yale 
Univ.,  New  Haven),  Amer.  Jour,  of  Physiol.,  11,  421,  1906. 

4Cf.  L.  Pollak  (Pharm.  Instit.,  Vienna),  Arch.  f.  exper.  Pathol.,  61,  1909; 
also  the  observations  of  K.  Hirayama  upon  the  interruption  of  sympathetic 
conduction  by  nicotine:    Zeitschr.  f.  exper.  Pathol.,  8,  649,  1911. 


302      ADRENALS  IN  CARBOHYDRATE  METABOLISM 

influence  of  hunger,  physical  exertion,  cold  or  earlier  injec- 
tions of  Suprarenin,  phloridzin,  etc.,  glycosuria  may  fail  to 
appear.  In  a  previous  lecture  occasion  was  taken  to  call 
attention  to  the  fact  that  the  economy  is  abundantly  provided 
with  means  to  maintain  the  sugar  in  the  blood  at  constant 
level  and  that  if  the  carbohydrate  elements  are  used  up  it  is 
in  position  to  build  sugar  de  novo  from  protein.  An  excel- 
lent example  of  this  process  is  afforded  in  recent  studies  of 
L.  Pollak,  who  has  been  able  to  show  in  the  Pharmacological 
Institute  in  Vienna  that  in  starving  rabbits  which  have  had 
their  glycogen  removed  by  strychnine  convulsions,  repeated 
administration  of  Suprarenin  in  increasing  dosage  may  in- 
duce an  accumulation  of  glycogen  in  the  liver,  of  proportions 
elsewhere  seen  only  in  animals  fed  upon  carbohydrates.  It 
is  of  interest  to  note  that  the  muscles,  which  usually  (as  the 
most  important  physiological  sites  of  glycogen  consump- 
tion) have  a  tendency  to  attract  the  carbohydrate  stores  from 
the  liver  for  their  own  purposes,  are  under  these  circum- 
stances entirely  or  almost  entirely  free  of  glycogen.5 

Dependence  of  Adrenin  Glycosuria  Upon  the  Renal 
Function. — Suprarenin  diabetes  should  undoubtedly  be 
classed  from  its  essential  character  among  the  glycosurias 
accompanied  by  hyperglycemia.  Whether  it  is  possible  to 
actually  find  at  a  given  moment  after  adrenin  application 
that  the  level  of  sugar  in  the  blood  is  distinctly  raised,  de- 
pends upon  the  precision  and  readiness  with  which  the  kid- 
ney affords  passage  of  a  surplus  of  sugar  from  the  blood  into 
the  urine.  Here,  too,  studies  in  the  Vienna  Pharmacologi- 
cal Institute  have  led  to  important  conclusions.  Thus  it 
has  been  proved  that  in  rabbits  a  proportion  of  0.15  to  0.25 
per  cent,  of  sugar  in  the  blood  will  give  rise  to  glycosuria 
only  in  case  a  marked  diuresis  coexists   (as  after  use  of 

5L.  Pollak  (Pharmakol.  Instit.,  Vienna),  Arch.  f.  exper.  Pathol.,  Gl,  166, 
1909;  cf.  therein  Literature:  Doyen  and  Kareff,  Gatin-Gruzewska,  Agadschi- 
ananz,  et  al.;  W.  B.  Drummond  and  D.  Noel  Paton,  Jour,  of  Physiol.,  31,  98, 
1904. 


ADRENIN  GLYCOSURIA  303 

caffein) ;  without  the  diuresis  the  glycosuria  remains  in 
abeyance.  If  the  proportion  of  sugar  in  the  blood  exceeds 
0.25  per  cent,  there  is  no  longer  necessity  for  the  diuresis  to 
put  the  glycosuria  in  operation.  After  repeated  subcuta- 
neous injections  of  adrenin,  however,  the  kidneys  may 
acquire  a  sort  of  tolerance,  making  it  possible  that  glyco- 
suria will  not  be  manifested  even  when  the  proportion  of 
sugar  in  the  blood  becomes  very  high.6  While  under  certain 
conditions  even  with  approximately  normal  proportions  of 
sugar  in  the  blood  a  glycosuria  can  be  caused  by  certain 
nephrotoxines  like  chromium,  uranium  or  corrosive  sub- 
limate (" renal  diabetes"),  there  are  other  renal  lesions  (as 
temporary  ligation  of  the  renal  artery),  according  to 
Ellinger  and  Seelig,7  which  promptly  inhibit  the  glycosuria 
caused  by  adrenalin.  There  is  scarcely  any  doubt  that  some 
alteration  of  the  renal  circulation  is  directly  concerned  with 
the  suppression  of  adrenin  glycosuria,  so  often  seen  after 
injection  of  lymphagogues  (extract  of  crab  meat,8  hirudin,9 
and  Witte 's  peptone  10),  in  infectious  diseases,11  and  experi- 
mentally produced  fever,12  after  extirpation  of  both 
adrenals,13  and  other  severe  operative  interferences,  after 
peritoneal  irritations  u  (which  may  be  produced  by  injec- 
tion of  trypsin  or  pancreatic  juice,  vide  supra,  p.  262),  after 
injections  of  calcium  chloride,15  etc. 

Occasion  was  taken  in  a  previous  lecture  to  point  out  that 
it  is  entirely  reasonable  to  believe  that  passage  of  adrenin 
from  the  adrenal  medulla  into  the  circulating  blood  takes 

6  L.  Pollak,  1.  c,  p.  157. 

7  A.  Ellinger  and  Seelig,  Münchener  med.  Wochensckr.,  1905,  No.  11. 

8  A.  Biedl  and  Offer,  Wiener  klin.  Wochenschr.,  1907,  1530. 
8  Mikulicich,  1.  c. 

10  K.  Glässner,  and  E.  Pick,  Zeitschr.  f.  exper.  Pathol.,  6,  1909. 

11  G.  Ghedini  and  G.  Mascerpa,  Folia  Clinica,  2,  H.  3,  cited  in  Centralbl.  f.  d. 
ges.  Biol.,  11,  No.  2508. 

12  Aronsohn,  Virchow's  Arch.,  174,  383,  1903. 

13  J.  Gautrelet  and  L.  Thomas,  C.  R.  Soc.  de  Biol.,  66,  798,  1909. 
"O.  v.  Fürth  and  C.  Schwarz,  Biochem.  Zeitschr.,  31,  113,  1911. 

15  F.  Schrank,  Zeitschr.  f.  klin.  Med.,  67,  230,  1908. 


304     ADRENALS  IN  CARBOHYDRATE  METABOLISM 

place  as  a  physiological  process.  It  is,  therefore,  not  at  all 
surprising  that  Herter  should  have  succeeded  in  bringing  on 
glycosuria  by  squeezing  the  normal  adrenals  in  situ. 

Hypothesis  of  the  Regulating  Influence  of  Adrenin  Upon 
Normal  Carbohydrate  Metabolism. — It  is  but  a  step  from 
this  point  to  the  proposition  that  the  passage  of  the  adrenin 
from  the  adrenals  into  the  blood  stream  has  normally  a 
regulative  influence  upon  carbohydrate  metabolism.  Thence 
it  is  suggested  that  the  adrenin  having  entered  the  circula- 
tion normally  from  the  adrenals  excites  the  sympathetic 
nerve  terminations  in  the  liver  (in  the  same  way  as  in  elec- 
tric irritation  of  the  sympathetic,  in  the  sugar  puncture,  in 
stimulation  of  the  central  end  of  the  vagus,  in  asphyxia,  in 
the  effect  of  carbon  monoxide,  caffein  and  many  of  the 
narcotics),16  and  that  such  a  condition  of  stimulation  can 
under  proper  conditions  give  rise  to  a  discharge  of  the 
hepatic  glycogen,  to  hyperglycemia  and  to  glycosuria. 

Does  the  Sugar  Puncture  Act  Through  the  Adrenals  to 
Cause  Glycosuria? — From  this  point  of  view  a  line  of  thought 
has  been  developed,  that  Claude  Bernard's  sugar  puncture 
may  possibly  not  have  a  direct  effect  upon  the  liver,  but  may 
perhaps  act  indirectly  by  way  of  the  adrenals,  inducing  pri- 
marily a  massive  output  of  adrenin  from  the  adrenals  into 
the  blood,  with  production  in  this  way  of  a  simple  adrenin 
glycosuria,  in  complete  analogy  to  the  effect  of  an  intra- 
venous injection  of  this  very  active  substance  into  the  cir- 
culation. 

Soon  after  F.  Blum,17  the  discoverer  of  adrenal  diabetes, 
published  his  belief  that  a  close  similarity  exists  between 
this  condition  and  glycosuria  from  Bernard's  puncture,  the 
logical  suggestion  from  which  would  be  to  investigate 
whether  the  latter  does  not  have  its  influence  on  the  liver 

16  E.  Starkenstein  (J.  Pohl's  Lab.,  Prague),  Zeitschr.  f.  exper.  Pathol., 
10,  1911. 

17  F.  Blum   (Frankfurt,  a.  M.),  Pfliiger's  Arch.,  90,  628,  1902. 


EXCLUSION  OF  ADRENALS  305 

through  the  adrenals,  the  glycosuric  puncture  was  studied 
from  this  view  point  by  quite  a  number  of  researchers. 

Let  us  consider  for  a  moment  what  objective  facts  we 
ought  to  demand  in  order  to  regard  as  proved  such  a  thor- 
oughly complicated  relation  as  the  above  mentioned 
hypothesis  assumes. 

We  should  expect  in  the  first  place  that  if  the  adrenals 
were  removed  the  glycosuric  puncture  would  be  without  its 
customary  effect.  We  might  further  very  properly  suppose 
that  a  massive  discharge  of  this  substance  would  be  fol- 
lowed by  a  noticeable  impoverishment  in  the  adrenal  medulla 
of  its  pressure-raising  chromogen.  And  finally  we  ought 
to  require  evidence  that  the  sugar  puncture  really  is  fol- 
lowed by  an  excessive  presence  of  Suprarenin  in  the  blood. 
Closer  examination  may  now  be  made  as  to  what  results 
experiments  have  afforded  which  may  be  applied  to  each 
one  of  these  postulates. 

Failure  of  Effect  of  Glycosuric  Puncture  After  Exclusion 
of  the  Adrenals. — The  first  point  to  be  made  (determined 
coincidently  by  A.  Meyers,  E.  Landau  and  R.  H.  Kahn)  is 
that  the  puncture  is  no  longer  capable  of  producing  glyco- 
suria when  the  adrenals  have  both  been  extirpated.  This 
is  all  the  more  notable  in  case  of  operated  animals  which 
survive  the  operation  for  some  length  of  time  and  are  in 
good  health.  In  such  animals,  too,  no  hyperglycemia  is 
met  from  splanchnic  irritation.18  The  plausible  explanation 
that  in  animals  deprived  of  their  adrenals  there  is  simply  a 
reduction  in  the  glycogen  supplies  may  hold  in  case  of  rats 
and  dogs,19  but  apparently  not  in  case  of  rabbits,  which  may 
survive  the  bilateral  removal  of  the  adrenals  for  as  much 

18  J.  J.  R.  Macleod  and  R.  G.  Pearce,  Amer.  Jour,  of  Physiol.,  29,  419,  1912; 
cf.  also  the  diuretin  experiments  of  M.  Nishi  (Pharmacol.  Instit.,  Vienna), 
Arch.  f.  exper.  Pathol.,  61,  401,  1909. 

18  0.  Schwarz    (E.  Pick's  Lab.,  Vienna),  Pflüger's  Arch.,  134,  259,   1910; 
O.  Porges  (v.  Noorden's  Clinic,  Vienna),  Zeitschr.  f.  klin.  Med.,  69,  3-4,  1909; 
10,  1910. 
20 


306       ADRENALS  IN  CARBOHYDRATE  METABOLISM 

as  a  year,  take  on  weight,  show  a  normal  amount  of  glyco- 
gen, and  differ  from  normal  animals  apparently  only  in  the 
fact  that  the  glycosuric  puncture  has  no  effect  on  them.20 
It  should  be  recalled,  too,  that  hypoglycemia  and  increased 
tolerance  for  sugar  has  been  met  in  sequence  to  removal  of 
the  two  adrenals  in  dogs  and  to  Addison's  disease  in  man.21 
Considerable  importance  on  the  other  hand,  should  be 
attributed  to  the  finding  that  even  in  animals  deprived  of 
the  adrenals  hyperglycemia  may  be  caused  by  irritation  of 
the  central  segment  of  the  vagus  nerve 22 ;  this  is  a  positive 
indication  that  the  ' '  sugar  centre ' '  can  exert  its  power  en- 
tirely independently  of  the  adrenals.  It  seems  possible, 
too,  that  the  failure  of  puncture  glycosuria  and  other  re- 
lated glycosurias  23  after  extirpation  of  the  adrenals,  in  the 
course  of  which  operation  it  is  not  unlikely  that  lesions  of 
the  network  of  nerves  about  the  kidney  may  have  been  pro- 
duced (in  line  with  what  has  already  been  said),  may  be  ex- 
plained with  much  probability  and  quite  fully  on  the  assump- 
tion of  some  disturbance  of  the  renal  circulation. 

Chromium  Affinity  of  the  Adrenals. — An  observation  of 
Kahn  is  directly  applicable  to  the  second  of  our  postulates. 
"If  one  adrenal  be  removed  from  a  rabbit  and  glycosuric 
puncture  be  performed,  and  the  second  adrenal  be  extirpated 
some  time  after  the  appearance  of  glycosuria,  it  will  be  found 
on  comparison  of  the  two  organs  that  the  second  one  re- 
moved has  undergone  very  decided  alteration.  The  affinity 
for  chromium  is  very  greatly  reduced,  the  cells  are  poor  in 
granules  and  rich  in  vacuoles ;  the  more  minute  vessels  are 
for  the  most  part  distended ;  and  its  adrenin  is  very  much 

20  R.  H.  Kahn  and  E.  Starkenstein  (Prague),  Pfliiger's  Arch.,  139,  181, 
1911. 

21  0.  Porges,  1.  c. 

22  E.  Starkenstein,  1.  c. 

23  Cf.  J.  J.  R.  Macleod  and  R.  G.  Pearce,  Amer.  Jour,  of  Physiol.,  29,  419, 
1912. 


ADRENIN  IN  BLOOD  IN  SUGAR  PUNCTURE        307 

reduced.  Section  of  the  corresponding  splanchnic  nerve 
protects  the  adrenal  from  these  changes  after  glycosuria 
puncture. ' ' 24 

Question  of  Increase  of  Adrenin  After  Sugar  Puncture. 
— What  of  the  third  and  most  important  of  our  postulates,  on 
which  in  fact  the  whole  hypothesis  stands  or  falls,  the  detec- 
tion of  an  increased  amount  of  Suprarenin  in  the  blood  after 
the  sugar  puncture?  While  Watermann  and  Smit 25  be- 
lieved they  had  found  an  increase  of  Suprarenin  in  the  blood 
after  sugar  puncture  by  means  of  the  frog's  eye  method,  not 
only  Kahn  26  but  also  E.  Th.  von  Brücke  27  failed  to  recog- 
nize such  an  increase.  It  should  be  said  that  the  latter  used 
in  determining  the  Suprarenin  in  the  blood  serum  the  very 
delicate  Trendelenburg-Läwen  test,  which  is  based  on  the 
idea  that  the  vasoconstrictor  power  of  a  solution  under  ex- 
amination may  be  tested  by  the  variation  in  escape  of  fluid 
when  perfused  through  the  hind  legs  of  a  frog.  Kahn 2S  has 
objected  to  the  force  of  this  experiment  because  after  sub- 
cutaneous administration  of  Suprarenin  in  small  doses,  but 
sufficient  to  cause  glycosuria,  it  is  impossible,  by  available 
methods,  to  recognize  any  accretion  of  this  substance  in  the 
blood. 

The  author  confesses  that  he  is  not  entirely  convinced  of 
the  extent  to  which  this  objection  is  justified.  For  if  the 
Suprarenin  passes  out  from  the  adrenals  into  the  circulation 
in  sugar  puncture,  it  does  so  not  by  a  subcutaneous  route  but 
intravenously.  As  Kahn  emphasized,  adrenin-glycosuria 
will  appear  in  half -grown  rabbits  from  doses  of  0.1  milli- 
gram upwards.    A  dose  of  this  size  given  intravenously 

24  R.  H.  Kahn  (Prague) ,  Pflüger's  Arch.,  11(0,  254,  1911. 

25  N.  Watermann  and  H.  J.  Smit,  Pflüger's  Arch.,  12k,  198,  1908. 
16  R.  H.  Kahn  (Prague),  Pflüger's  Arch.,  128,  519,  1909. 

27  E.  Th.  von  Brücke  (Leipzig),  Münchener  med.  Wochenschr.,  1911,  No. 
26;   T.  Negrin  y  Lopes  (Physiol.  Instit..  Leipzig) ,  Pflüger's  Arch.,  1^5,  311,  1912. 

28  R.  H.  Kahn  (Prague),  Pflüger's  Arch.,  1U,  251,  1912. 


308     ADRENALS  IN  CARBOHYDRATE  METABOLISM 

would  show  a  powerful  vasoconstricting  effect  unless  in 
injection  it  were  spread  out  over  a  long  space  of  time.  Each 
one  of  us  will  necessarily  value  the  above  objection  accord- 
ing to  his  own  idea  whether  the  adrenal  medullary  substance, 
from  a  stimulus  passing  along  the  nerve  paths  to  it,  dis- 
charges its  store  of  Suprarenin  suddenly,  or  whether  it 
allows  it  to  ooze  out  slowly.  But  this  is  the  same  old  story: 
as  long  as  an  accumulation  of  adrenin  in  the  blood  after 
the  glycosuric  puncture  is  not  actually  proved,  we  will  lack 
authority  for  assuming  that  the  puncture  glycosuria  is 
caused  by  such  means.  Here  is  a  place  in  physiology  where 
we  are  forced,  if  we  are  not  willing  to  lose  the  ground  under 
our  feet,  to  hold  on  to  things  we  can  see,  even  if  we  are  very 
well  aware  that  there  is  plenty  which  we  do  not  see.  It  has 
been  well  said  "that  the  negative  finding  in  reference  to  the 
sugar  puncture  proves  nothing  more  than  the  impossibility 
of  demonstrating  an  adrenaemia  from  this  disturbance  but 
in  no  way  contradicts  the  possibility  of  its  existence. ' ' 29  We 
are  here  not  after  something  that  is  possible  (many  things 
are  possible),  but  something  that  is  probable.  The  fact  that 
a  hypothesis  starts  up  in  an  investigator's  brain  and  that 
at  the  time  we  are  not  in  position  to  fully  prove  its  incorrect- 
ness does  not  force  us  by  a  great  deal  to  accord  reality  to 
it.  It  does  not  lie  at  our  door  to  bring  proof  that  a  hypo- 
thesis is  incorrect;  but  whoever  proposes  a  hypothesis  has 
to  bring  the  positive  proof  that  it  is  correct.  In  this  way 
and  not  in  the  reverse  we  hold  in  other  exact  sciences,  and  so, 
too,  it  should  be  held  in  physiology. 

Here  is  a  rare  little  verse  which  perhaps  has  occurred 
to  some  in  this  connection : 

1  l  Oh,  learned  man,  'tis  thus  I  know  you,  face  to  face ! 
What  you  don 't  touch  stands  miles  from  you  apace ; 
What  you  don't  grasp,  for  you  is  gone  for  woe  and  weal; 

29  R.  H.  Kahn,  Pflüger's  Arch.,  1U,  271,  1912. 


DO  ADRENALS  HAVE  REGULATING  INFLUENCE  ?    309 

What  you  don't  see,  you're  sure  cannot  be  real; 
What  you  don't  weigh,  ne'er  has  a  weight  for  you; 
What  you  don't  coin,  you  think  don't  count  a  sou." 

The  author  will  not  evade  the  point.  But  for  the  present 
in  biochemistry  we  make  the  most  progress  if  we  hold  to  the 
things  we  can  see,  and  weigh  and  count. 

Do  the  Adrenals  Have  a  Regulating  Influence  on  the 
Normal  Carbohydrate  Metabolism? — Even  were  a  positive 
proof  obtained  that  the  sugar-puncture  acts  essentially  like 
an  adrenin  glycosuria,  it  would  still  be  far  from  proving 
that  under  normal  physiological  conditions  the  internal 
secretion  of  the  adrenals  possesses  a  regulative  effect  on  the 
metabolism  of  carbohydrates.  Even  if  a  sudden  massive 
expulsion  of  Suprarenin  from  the  adrenal  medulla  does  cause 
a  glycosuria  this  might  very  well  be  a  toxic  glycosuria,  of 
which  there  are  so  many  examples. 

Whether  the  minimal  quantities  of  adrenin  which  in 
normal  conditions  enter  the  blood  have  anything  to  do  with 
the  liquidation  of  the  glycogen  stores  and  with  the  regula- 
tion of  carbohydrate  metabolism,  remains,  therefore,  an 
open  question,  although  many  writers  today  regard  a  rela- 
tion of  this  sort  as  a  settled  fact.  Thus  Falta  30  thinks  that 
every  diabetic  disturbance  of  metabolism  may  be  looked 
upon  as  a  predominance  of  sympathetic  impulses  over  the 
autonomous  ones.  "If  the  cause  of  it  is  seen  rather  in  some 
insufficiency  of  the  pancreas  it  is  proper  to  speak  of  a  pan- 
creatogenous diabetes ;  if  it  is  rather  in  an  excessive  func- 
tion of  the  circulatory  system,  to  say  it  is  an  adrenalogenous 
one. ' '  It  should  be  added,  however,  that  the  recognition  of 
a  hypoglycemia  and  increased  tolerance  for  carbohydrates 
in  a  few  cases  of  Addison's  disease  31  is  in  direct  contrast  to 

30  W.  Falta,  Prager.  med.  Woehenschr.,  1910,  No.  7. 

31  O.  Porges,  1.  c. ;  H.  Eppinger,  W.  Falta  and  C.  Rudinger,  Zeitschr.  f . 
klin.  Med.,  66,  50,  1908. 


310     ADRENALS  IN  CARBOHYDRATE  METABOLISM 

observations  in  which  in  rabbits  with  adrenals  removed  the 
amount  of  sugar  in  the  blood  was,  as  a  rule,  found  not 
reduced.32  0.  Schwartz,  who  found  that  the  glycosuric 
effect  of  phloridzin  was  entirely  preserved  in  rats  deprived 
of  their  adrenals,  concludes  after  a  critical  discussion  of  the 
above  statements  that ' '  the  assumption  of  a  sugar-mobiliz- 
ing function  of  adrenin,  hitherto  accepted  without  any  direct 
experimental  basis,  can  no  longer  be  maintained. " 33  In 
view  of  the  recognized  antagonism  between  the  sympathetic 
and  autonymous  nerve  systems  and  the  fact  that  almost 
always,  where  organs  have  a  double  innervation,  this  double 
supply  is  an  antagonistic  one,  and  stimulation  of  the  sym- 
pathetic fibres  produces  characteristically  the  opposite 
action  from  that  of  the  autonymous  nerves,34  it  is  quite  well 
worth  observing  that  the  glycosuria  produced  by  adrenin 
is  not  influenced  by  its  antagonists,  cholin  and  pilocarpin. 
This  certainly  does  not  speak  in  favor  of  the  assumption 
that  sugar  metabolism  is  subject  to  a  delicate  regulation  by 
Suprarenin  through  stimulation  of  the  sympathetics.35 

An  idea  has  also  been  suggested  that  the  adrenals  influ- 
ence sugar  metabolism  in  some  way  through  the  pancreas. 
But  for  this  view,  also,  there  is  no  definite  basis ;  in  geese 
and  ducks,  in  which  extirpation  of  the  pancreas  does  not 
occasion  sugar  excretion,  Suprarenin  produces  glycosuria 
even  after  removal  of  the  pancreas.36  The  pancreas  is,  of 
course,  not  responsible  for  the  production  of  this  effect. 

So  much  for  the  relation  of  the  adrenals  to  carbohydrate 
metabolism. 


83  E.  Frank  and  S.  Isaak  (Wiesbaden),  Zeitschr.  f.  exper.  Pathol.,  7,  326, 

1909. 

83  O.  Schwarz  (E.  Pick's  Lab.,  Vienna),  Pflüger's  Arch.,  13k,  257,  1910;  cf. 
also  J.  J.  R.  Macleod  and  R.  G.  Pearce,  Amer.  Jour,  of  Physiol.,  29,  419,  1912. 

31  Cf.  H.  H.  Meyer  and  R.  Gottlieb,  Exper.  Pharmacol.,  p.  122,  1910,  and 
A.  Fröhlich  (Pharmakol.  Instit.,  Vienna),  Med.  Klinik,  1911,  No.  8. 

85  E.  Frank  and  S.  Isaak,  1.  c. 

38  Noel  Paton,  Jour,  of  Physiol.,  32,   59,   1909. 


REMOVAL  OF  THYROID  311 

RELATIONS  OF  THE  THYROID  GLAND  TO  CARBOHYDRATE 

METABOLISM 

We  next  turn  to  a  no  less  knotty  and  troublesome  sub- 
ject, the  problem  of  the  relation  of  the  thyroid  gland  to  the 
carbohydrate  metabolism  of  the  body. 

Removal  of  the  Thyroid  and  of  the  Parathyroids. — In  or- 
der to  prevent  confusion  it  is  necessary  to  strictly  differenti- 
ate between  the  thyroid  gland  and  the  parathyroid  bodies. 
From  studies  of  cases  of  myxcedema  37  and  upon  dogs  after 
extirpation  of  their  thyroids,  a  decided  increase  of  sugar 
tolerance  has  been  observed  following  loss  of  the  thyroid 
function,  and  with  this  a  marked  general  slowing  of  the 
transformation  processes.38  Thus  a  dog  without  its  thyroid 
can  tolerate  very  large  quantities  of  ingested  sugar  without 
the  appearance  of  an  alimentary  glycosuria.  So,  too, 
adrenin  glycosuria  may  fail  to  appear  in  different  animals 
under  certain  conditions  (although  by  no  means  always) 
after  extirpation  of  the  thyroid.39  Removal  of  the  para- 
thyroids, however,  has  precisely  the  opposite  effect  (as  indi- 
cated in  the  studies  of  R.  Hirsch,  Underbill  and  Saiki,  and  of 
Eppinger,  Falta  and  Rudinger).  Even  after  extirpation 
of  three  parathyroids  in  dogs  there  may  be  noted,  in  the 
course  of  a  latent  tetany  (which  is  without  spasmodic 
twitching  and  is  only  told  by  a  typical  change  in  electrical 
excitability) ,  an  enormous  lowering  of  the  assimilation  limit 
for  grape-sugar.  If  there  be  combined  with  the  extirpation 
of  several  of  the  parathyroids  also  extirpation  of  the  pan- 
creas, a  marked  rise  in  the  protein  exchange  in  fasting  and 

"  J.  Hirschl,  W.  Knopf elmacher  (cf.  Vol.  I  of  this  series,  p.  439,  Chemistry 
of  the  Tissues)   and  C.  v.  Noorden,  Die  Zuckerkrankheit,  5th  ed.,  p.  47,  1910. 

38  Pari,  Falta  and  Gigon,  H.  Eppinger,  W.  Falta,  C.  Rudinger  (v.  Noor- 
den's  Clinic),  Zeitschr.  f.  klin.  Med.,  66,  1908;    67,  1909. 

29  Eppinger,  Falta  and  Rudinger,  1.  c. ;  E.  P.  Pick  and  F.  Pineles,  Biochem. 
Zeitschr.,  12,  473,  1908;  F.  P.  Underhill  and  W.  H.  Hilditch,  Amer.  Jour,  of 
Physiol.,  25,  66,  1909;  F.  P.  Underhill.  ibid.,  21,  331,  1911;  Ritzmann 
(Straub's  Lab.).  Arch.  f.  exper.  Pathol.,  61,  231,  1909;  E.  G.  Grey  and  W.  T. 
de  Santelle  (Johns  Hopkins  Univ.,  Baltimore),  Jour,  of  Exper.  Medicine,  11, 
659,  1909;    J.  McCurdy,  ibid.,  798. 


312    THYROID  GLAND  IN  CARBOHYDRATE  METABOLISM 

coincidently  an  increase  in  the  D/N  quotient  to  as  much  as 
3.5  (as  seen  in  the  height  of  phloridzin  diabetes).40  Possibly 
with  these  facts  in  view  we  may  assume  that  we  are  justified 
in  looking  upon  the  thyroid  and  parathyroids  as  antagonistic 
in  their  relations  to  carbohydrate  metabolism.  However, 
the  whole  matter  seems  by  no  means  thoroughly  established. 

Hyperthyroidism. — Hyperthyroidism  lowers  the  assimi- 
lation limit  for  sugar.  Transitory  glycosurias  have  been  met 
time  after  time  after  feeding  thyroid  tissue  (cf.  Vol.  I  of 
this  series,  p.  448,  Chemistry  of  the  Tissues).  In  special 
cases  the  occurrence  of  true  diabetes  has  been  noted,  which 
may,  however,  be  nothing  more  than  the  manifestation  of  a 
previously  existing  disposition  toward  the  affection  (as 
C.  v.  Noorden  believes).  In  Basedow's  disease,  too,  which 
we  are  for  the  present  justified  in  regarding  as  a  form  of 
hyperthyroidism  (cf.  Vol.  I  of  this  series,  p.  456,  Chemistry 
of  the  Tissues),  there  may  be  frequently  seen  instances  of 
alimentary  glycosuria  (first  discovered  by  Ludwig  and 
Kraus,  and  by  Chvostek  and  confirmed  by  many  later  ob- 
servers). This  is  to  be  expected,  according  to  the  observa- 
tions of  Eppinger  in  C.  v.  Noorden 's  Clinic,  in  those  cases  of 
Basedow's  disease  which  show  symptoms  of  sympathetic 
irritation,  and  is  usually  absent  from  those  cases  in  which 
symptoms  of  vagotonia  are  prominent.41 

Interaction  of  the  Internal  Secretory  Glands. — Eppin- 
ger, Falta  and  Rudinger  have  come  to  very  definite  ideas  as 
to  the  interaction  of  the  internal  secretory  glands,  to  which 
they  ascribe  a  regulative  influence  over  normal  carbohy- 
drate metabolism.  They  assume  that  exclusion  of  a  "blood 
gland"  will  give  rise  to  two  distinct  effects,  primarily  direct 
influences  from  the  loss  of  the  specific  secretion  and  sec- 
ondarily indirect  influences  through  disturbance  of  its  inter- 
relation with  other  glands. 

40  Eppinger,  Falta  and  Rudinger,  1.  c. ;  also  R.  Hirsch  (F.  Kraus's  Clinic, 
Berlin),  Zeitschr.  f.  exper.  Pathol.,  3,  393,  1906;  5,  233,  1908;  Handb.  d. 
Biochem.,  8',  295,  329,  1910. 

41  C.  v.  Noorden's  Die  Zuckerkrankheit,  5th  ed.,  p.  46,  1910. 


INTERACTION  OF  INTERNAL  SECRETORY  GLANDS  313 

The  following  schema  is  intended  to  represent  the  mutual 
relations  of  the  thyroid,  adrenals  and  pancreas : 


PANCREAS 


CHROMAFFINE 


Inhibition  8YSTEM 

If  we  keep  perfectly  clearly  before  us  the  fact  that  this 
interrelation  is  of  an  absolutely  hypothetical  nature,  the 
most  of  us  will  not  be  disposed  to  deny  a  heuristic  value  to 
such  schematic  presentation. 

It  may  well  be  that  we  can  classify  the  ductless  glands 
in  two  groups,  one  group  with  an  accelerator,  the  other  with 
a  retarding  functional  effect  upon  the  metabolism.  The 
first  group,  whose  "hormones"  apparently  excite  sympa- 
thicotonic impulses,  includes  the  thyroid,  the  chromaffine  sys- 
tem and  perhaps  the  hypophysis.  To  the  second,  seem- 
ingly antagonistic  to  the  first  group,  belong  the  pancreas  and 
the  parathyroids.  The  first  group  could  stimulate  the  basic 
protein  destruction,  carbohydrate  mobilization,  fat  meta- 
bolism, output  of  water  and  salt,  and  the  galvanic  irritabil- 
ity of  nerves;  the  second  group,  however,  acts  according 
to  all  appearance  in  an  inhibitory  manner.42  The  strongest 
criticism,  unquestionably,  comes  when  we  discriminatively 
examine  the  mutual  relations  of  these  functions.  The  idea 
that  a  centre  in  the  medulla  regulates  the  provision  of  sugar 
to  the  various  tissues,  which,  as  Falta  supposes,  "continu- 
ously mobilizes,  by  way  of  the  sympathetic  nerves  and  the 
adrenals,  sugar  in  the  liver,  but  exerts  inhibitory  influences 

42  W.  Falta,  Wiener  klin.  Wochenschr.,  1909,  p.  1059 ;  Caro,  Med.  Klinik, 
1910,  136;  W.  Falta,  L.  H.  Newburgh  and  E.  Nobel  (v.  Noorden's  Clinic, 
Vienna),  Zeitschr.  f.  klin.  Med.,  72,  97,  1911. 


314     HYPOPHYSIS  IN  CARBOHYDRATE  METABOLISM 

on  this  mobilization  by  the  autonymous  nerves  and  pancreas, 
and  thus  the  level  of  sugar  in  the  blood  is  kept  at  a  constant 
level, ' '  is,  it  is  true,  very  plausible.  But  actually  such  inter- 
dependence is  far  from  proven  (and  this  should  be  clearly 
understood) . 

RELATION     OF    THE     HYPOPHYSIS    TO     CARBOHYDRATE 

METABOLISM 

Perhaps  nothing  can  illustrate  more  clearly  how  ex- 
tremely difficult  it  is  to  come  to  any  definite  conclusions  in 
this  field  of  our  study  than  a  statement  of  the  relations  of 
the  hypophysis  to  carbohydrate  metabolism. 

As  previously  stated  (Vol.  I  of  this  series,  p.  484,  Chem- 
istry of  the  Tissues),  Borchhardt  succeeded  in  inducing  a 
glycosuria  in  rabbits,  but  not  in  dogs,  by  injections  of  ex- 
tract of  the  hypophysis.  Later,  after  a  careful  review  of 
the  whole  literature  bearing  upon  the  subject,  he  came  to 
the  conclusion  that  glycosuria  is  a  more  constantly  associ- 
ated feature  in  cases  of  acromegaly  (in  which  it  may  be 
assumed  that  the  hypophysis  is  the  part  primarily  involved) 
than  in  any  other  affection.43  It  is  very  interesting  in  this 
connection  that  B.  Aschner,44  from  recent  investigations  of 
his  own  carried  out  in  R.  Paltauf  's  Institute,  holds  that  there 
exists  a  sugar  centre  in  the  vicinity  of  the  hypophysis.  After 
Kreidl  and  Karplus,  colleagues  of  the  writer,  had  succeeded 
in  the  Vienna  Physiological  Institute  in  showing  a  sympa- 
thetic nervous  centre  in  immediate  proximity  to  the  tuber 
cinereum,  Aschner  found  that  it  was  possible  to  produce  a 
glycosuria  with  absolute  certainty  by  injuring  the  tuber 
cinereum.  "If  we  grant,"  suggests  Aschner,  "that  over- 
activity of  the  hypophysis  itself,  just  as  overactivity  of  the 
thyroid  in  Basedow's  disease,  can  give  rise  at  times  to  a 
glycosuria,  it  seems  much  more  probable  from  the  foregoing 
experiment  (production  of  glycosuria  from  injury  to  the 

43  L.  Borchhardt  ( Jaffe's  Lab.,  Königsberg),  Zeitschr.  f.  klin.  Med.,  66,  3-4, 
1908. 

**B.  Aschner,  Pfliiger's  Arch.,  1^6,  114,  1912. 


INTERACTION  OF  INTERNAL  SECRETORY  GLANDS  315 

tuber  cinereum)  that  the  glycosuria  of  hypophyseal  affec- 
tions may  be  explained  as  depending  upon  an  irritation  of 
the  base  of  the  brain.  This  is  the  more  likely  because  of  the 
existence  here  of  both  vagus  and  sympathetic  paths,  and  an 
irritation  of  the  sympathetic  is  apparently  directly  capable 
of  giving  rise  to  glycosuria." 

In  this  connection  it  seems  to  be  of  great  interest  that  it 
has  been  found  possible  in  R.  Gottlieb  's  laboratory  to  pro- 
duce a  sensitization  of  sympathetic  nerve  endings  by  consti- 
tuents of  the  hypophysis  in  the  same  way  that  this  had  been 
previously  accomplished  by  components  of  the  thyroid  (Vol. 
I  of  this  series,  p.  457,  Chemistry  of  the  Tissues).  Proof  of 
sensitization  of  the  points  of  attack  of  Suprarenin  was  ob- 
tained both  by  the  Läwen-Trendelenburg  frog  preparations 
and  by  mydriasis  of  the  enucleated  frog's  eye.  Emphasis 
has  been  properly  laid  upon  the  point  that  as  long  as  we 
know  nothing  of  an  internal  secretion  of  the  constituents  of 
the  hypophysis  we  are  really  not  in  position  to  insist  upon 
the  physiological  significance  of  this  phenomenon.  We  can- 
not help,  however,  considering  such  sensitizing  of  the  points 
of  attack  of  one  internal  secretion  by  another  internal  secre- 
tion in  trying  to  explain  the  physiological  balance  of  the 
system  and  its  disturbances.45 

A  rather  impressive  complement  to  the  above-mentioned 
discoveries  may  be  recognized  in  the  observations  of 
B.  Aschner 46  according  to  which  in  young  dogs  the  glyco- 
suria caused  by  adrenin  may  be  markedly  suppressed  by 
extirpation  of  the  hypophysis,  possible  not  only  in  the  first 
few  days  after  the  operation  but  for  months.  It  is  espe- 
cially noteworthy  that  the  skin  necroses,  which  so  often 
occur  in  case  of  adrenin  injections,  are  not  met  in  such  in- 
stances at  all  or  only  rarely.  This,  it  might  be  suggested, 
may  be  due  to  the  fact  that  the  vaso-constricting  influence 
of  the  adrenin  has  been  weakened. 

"Kepinow  (R.  Gottlieb's  Lab.,  Heidelberg),  Arcb.  f.  exper.  Patbol.,  67, 
247,  1912. 

«Aschner,  1.  c,  pp.  105-106. 


316     HYPOPHYSIS  IN  CARBOHYDRATE  METABOLISM 

Consistently  with  the  failure  of  adrenin  glycosuria  in 
animals  deprived  of  their  hypophyses,  in  hypophyseal 
obesity  (degeneratio  adiposo-genitalis),  which  is  believed 
to  be  connected  with  a  lowered  function  of  the  hypophysis,  a 
higher  tolerance  for  carbohydrates  has  been  observed,  as 
in  myxcedema.47  As  previously  stated,  the  hypophysis  may 
be  regarded  as  associated  with  the  thyroid  and  the  chrom- 
affine  system  in  a  group  of  organs  with  sympathetic  innerva- 
tion, having  an  accelerator  influence  upon  metabolism,  and 
under  proper  circumstances  increasing  the  respiratory 
metabolism  as  well  as  the  carbohydrate-,  protein-  and  fat- 
exchange.  Aschner  48expresses  this  relation  by  the  follow- 
ing modification  of  the  previously  presented  Eppinger-Falta 
schema  (including  the  ovary  and  the  parathyroids) : 

THYROID 
HYPOPHYSIS 


PANCREAS 

PARATHYROIDS 

OVARY 


Inhibition 


CHROMAFFINE 
SYSTEM 


Without  any  desire  to  place  any  excessive  provisional 
estimate  upon  the  reality  of  all  these  matters,  it  will  be  well 
for  us  to  follow  with  proper  interest  the  further  development 
of  this  modern  scientific  magic,  in  which  internal  secretory 
organs  replace  the  planetary  orbits  of  the  ancient  astrol- 
ogers, with  their  favoring  and  inhibitory  influences  upon 
every  phase  of  life. 

With  this,  these  little  known  subjects  may  be  dismissed, 
and  with  them  that  of  glycosuria,  attention  being  directed 
to  other  matters  connected  with  carbohydrate  metabolism ; 
of  which  the  first  to  demand  our  interest  are  the  glycuronic 
acids. 

47  Cf.  C.  v.  Noorden,  Die  Zuckerkrankheit,  5th  ed.,  1910,  p.  48. 
"'Aechner,  1.  c,  p.  110. 


GLYCURONIC  ACID  317 

GLYCURONIC  ACID 

Constitution. — Glycuronic  acid,  which  was  discovered  as 
a  product  of  metabolism  in  1878  by  M.  Jaffe  and  by  0. 
Schmiedeberg  and  H.  H.  Meyer,  contemporaneously  but  in- 
dependently, and  the  constitution  of  which  was  verified  by  its 
synthetic  production  by  Emil  Fischer  and  Piloty,  is  without 
doubt  a  direct  oxidation  product  of  grape-sugar : 

GLUCOSE  GLYCURONIC  ACID 

COH  COH 

H.C.OH  H.C.OH 

I  I 

OH.C.H  OH.C.H 

I  >  I 

H.C.OH  H.C.OH 

I  I 

H.C.OH  H.C.OH 

I  I 

[CH2.OH  COOH. 

Glycuronic  acid  in  metabolism  always  appears  in  the 
form  of  conjugated  glycuronic  acids  which  are  laevorotary, 
an  optical  dextrogyration  being  characteristic  of  the  free 
glycuronic  acid. 

The  conjugates  are  in  general  of  the  nature  of  alcohols 
or  phenols.  According  to  the  synthesis  by  Neuberg  and 
Neimann  and  the  discovery  that  glucoside-splitting  fer- 
ments (like  emulsin  and  kefirlactase)  are  also  capable  of 
splitting  conjugated  glycuronic  acids,  there  is  no  room  for 
doubt  that  in  a  general  way  these  latter  correspond  to  the 
glucoside  type  of  Emil  Fischer.  Starting  with  the  tauto- 
meric, accessory  form  of  glucose 

CH.OH 
H.C.OH 
OH.C.H 

ni 

H.C.OH 

I 
CH2.OH, 

the  reaction  with  an  alcohol  obviously  takes  place  with 
separation  of  water  and  oxidation  of  the  terminal  CH2.0H 


318  GLYCURONIC  ACID 

group  to  a  carboxyl,  thus  giving  a  phenol-glycuronic  acid 
the  constitution: 

CH.O.C6H6 

H.C.OH 

I 
OH.C.H 

I 
H.C 

I 
H.C.OH 

COOH. 

According  to  Emil  Fischer  it  is  very  improbable  that  free 
glycuronic  acid  is  first  formed,  as  it  cannot  well  be  imagined 
why  the  CH2(OH)  group  should  be  oxidized  while  the  much 
more  labile  aldehyde  group  is  preserved.  However,  this 
objection  is  of  less  force  if  one  supposes  that  the  aldehyde 
group  is  protected  by  first  fixing  an  alcohol  or  a  phenol 
group,  after  which  the  terminal  CH2OH  group  undergoes 
oxidation  into  COOH. 

Conjugation  Conditions. — Very  many  foreign  substances 
when  introduced  into  the  body  are  finally  excreted  with  the 
urine  in  the  form  of  conjugate  glycuronic  acids.  However, 
the  alcohols  and  phenols  alone  are  capable  of  direct  conjuga- 
tion. Aldehydes  and  acetones  must  first  be  reduced  to  alco- 
hols (as  chloral,  CCl3.COH,  to  CCL.CH2.OH;  acetone,  CH3. 
CO.CH3,  to  CH3.CH(OH).CH3).  Hydrocarbons  of  the  aro- 
matic and  hydroaromatic  series  are  hydroxylized  (as  ben- 
zol into  phenol) ;  and  heterocyclic  compounds  undergo 
analogous  hydroxylation  (as  indol  into  indoxyl).  These 
relations  have  been  thoroughly  proved  by  numerous  studies 
by  Jaffe,  Neuberg,  Fromm,  Hildebrandt,  Neubauer,  Hämä- 
läinen,  and  others.49 

**  Cf.  Literature:  C.  Neuberg,  Handb.  d.  Pathol,  d.  Stoffw.,  2d  ed.,  2,  225, 
228,  1907,  and  Ergebn.  d.  Physiol.,  3,  385-390,  1904;  C.  Neuberg  and  W.  Nei- 
mann,  Zeitschr.  f.  physiol.  Chem.,  M,  114  1905;  E.  Salkowski  and  C.  Neuberg, 
Biochem.  Zeitschr.,  2,  307,  1906;  R.  Hildebrandt  (Halle),  Hofmeister's  Beitr., 
7,  438,  1906;  Hämäläinen  (Helsingfors) ,  Skandin.  Arch.  f.  Physiol.,  27,  141, 
1912;  J.  Schüller  (M.  Cremer's  Lab.,  Cologne),  Zeitschr.  f.  Biol.,  56,  274,  1911; 
J.  Saneyoshi  (C.  Neuberg's  Lab.),  Biochem.  Zeitschr.,  86,  22,  1911. 


ORIGIN  OF  GLYCURONIC  ACID  319 

In  determining  the  amount  of  aromatic  substances  ex- 
creted in  the  urine  it  is  necessary  besides  the  conjugated 
sulphuric  acids  to  also  keep  in  mind  the  conjugated  gly- 
curonic  acids,  with  possible  complex  interrelations.  Thus 
Neuberg  isolated 50  from  the  urine  of  dogs  to  which  cresol 
had  been  fed,  the  barium  salt  of  a  double  combination  of 
cresol-glycuronic  acid  and  cresol-sulphuric  acid: 

CH.O—C^.CH, 

H.C.OH 
OH.C.H. 

I 

H.C.OH 

COO— Ba— O— S02— O— CeH^.CHs. 

Properly  considered  the  conjugation  of  foreign  substances 
with  glycuronic  acid  is  really  a  detoxifying  process.  Ap- 
parently the  economy  sometimes  provides  a  larger  amount 
of  glycuronic  acid  than  is  absolutely  needed.  At  least 
F,  Blumenthal  noticed  in  a  case  of  lysol  poisoning  the  form- 
ation of  considerably  more  glycuronic  acid  than  required 
for  fixing  the  amount  of  cresol  introduced. 

Origin  of  Glycuronic  Acid  from  Oxidation  of  Sugar. — 
The  origin  of  glycuronic  acid  from  sugar  by  oxidation 
(which  can  be  performed  artificially  in  vitro  by  careful  oxi- 
dation of  dextrose  by  means  of  peroxide  of  hydrogen)  51 
directly  explains  a  positive  dependence  of  the  physiological 
formation  of  this  substance  upon  the  body  supply  of  carbo- 
hydrates. One  can  readily  appreciate  that  an  animal,  with 
its  glycogen  reduced  from  long  continued  starvation,  would 
react  to  dosage  with  camphor  with  only  a  slight  excretion 
of  glycuronic  acid,  and  that  this  would  increase  progressively 
with  exhibition  of  sugar.  And  when  it  is  recalled  that  sugar 
may  be  formed  from  protein,  there  is  just  as  little  occasion 

60  C.  Neuberg  and  E.  Kretschmer,  Bioehem.  Zeitschr.,  36,  15,  1911;  cf.  also 
F.  Stern  (Kiel),  Zeitschr.  f.  physiol.  Chem.,  68,  52,  1910. 
51  A.  Jolles,  Bioehem.  Zeitschr.,  3-',,  242,  1911. 


320  GLYCURONIC  ACID 

for  surprise  to  find  that  a  practically  glycogen-free  indivi- 
dual is  still  capable  of  producing  some  glycuronic  acid.  The 
problem  of  its  production  is  to-day  not  so  much  as  to  its 
derivation  from  sugar  (for  this  surely  can  no  longer  be  a 
subject  of  doubt),  but  whether  physiologically  the  normal 
catabolism  of  sugar  proceeds  through  glycuronic  acid.  In 
the  sense  of  Paul  Meyer's  much,  discussed  "theory  of  in- 
complete sugar  oxidation"  many  instances  of  pathological 
glycuronic  acid  excretion,  not  satisfactorily  explicable  on 
the  assumption  of  an  increased  introduction  or  formation  of 
substances  able  to  combine  with  it,  may  be  looked  on  as  due 
to  a  primary  disturbance  of  the  normal  sugar  catabolism, 
here  becoming  stationary  in  the  intermediate  stage  of 
glycuronic  acid.  This  might  be  thought  of  in  many  in- 
stances of  glycuronic  acid  excretion  in  respiratory  disturb- 
ances, in  many  intoxications,  in  very  free  glycogen  supply, 
and  therefore  in  diabetes.  Paul  Meyer  believes,  too,  that  a 
heightened  excretion  of  glycuronic  acid  without  evident 
cause  and  without  coincident  increase  of  elimination  of 
aromatic  conjugates  in  apparently  healthy  individuals  may 
be  looked  upon  as  a  precedent  of  diabetes  and  as  a  symptom 
of  incomplete  oxidation  of  sugar.  Neuberg  very  properly 
suggests,  however,  that  Paul  Meyer  has  not  presented 
exact  proof  of  the  correctness  of  his  theory ;  that  it  can  only 
be  looked  on  for  the  present  as  a  simple  expression  of  the 
facts  observed  by  him  and  may  perhaps  eventually  be  ex- 
plained in  a  totally  different  way.52  C.  von  Noorden,  who 
does  not  favor  the  theory  above  outlined,  thinks  it  incorrect 
to  assign  importance  to  increase  of  glycuronic  acid  in 
diabetes.53 

Oxaluria. — The  circumstance  that  free  supply  of  sugar 
and  glycuronic  acid  may  lead  to  an  increased  elimination  of 
oxalic  acid  and  to  an  increased  accumulation  of  this  acid  in 
the  liver,  and  the  fact  that  oxaluria  and  glycuronic  acid  ex- 

52  C.  Neuberg,  Handb.  d.  Pathol,  d.  Stoffwechs.,  2d  ed.,  2,  233-235,  1907. 
63  C.  von  Noorden,  Handb.  d.  Pathol,  d.  Stoffwechs.,  2d  ed.,  2,  60,  1907. 


CONVERSION  OF  GLYCURONIC  ACID  321 

cretion  are  at  times  found  associated  with  diabetes,  has  been 
the  basis  for  regarding  oxalic  acid  as  an  end-product  of 
sugar  catabolism: 

Sugar >  Glycuronic  Acid >•  Oxalic  Acid. 

That  oxalic  acid  may  be  an  end-product  of  all  sorts  of  sub- 
stances has  probably  been  the  uncomfortable  experience  of 
every  chemist,  who  after  having  carried  out  some  tiresome 
oxidation  experiment  has  time  after  time  been  able  to  obtain, 
instead  of  the  product  he  hoped  for,  only  the  inevitable  and 
unwelcome  oxalic  acid.  Of  course,  then,  it  cannot  be  denied 
that  sometimes  sugar  may  also  be  converted  into  oxalic  acid 
in  the  body.  When  and  under  what  circumstances  this  is 
true  is,  however,  unknown ;  and  thus  far  all  told  there  has 
very  little  of  a  positive  nature  been  obtained  from  the 
many  studies  of  the  elimination  of  the  relatively  incom- 
bustible oxalic  acid  in  physiological  and  pathological 
conditions.54 

Conversion  of  Glycuronic  Acid  into  ^-xylose. — A  very  im- 
portant phase  of  the  glycuronic  acid  question  has  been 
previously  referred  to,  the  conjectural  relation  of  the  acid 
with  the  tissue  pentoses.  From  E.  Salkowski's  and  C.  Neu- 
berg's  discovery  it  is  at  least  quite  probable  that  the  tissue 
sugar  with  five  carbon  atoms,  A-xylose,  arises  from 
glycuronic  acid  by  cleavage  of  C02,  and  that  the  latter  may 
be  thus  converted  into  pentose  by  the  agency  of  putrefactive 
microorganisms : 

GLYCURONIC  ACID  X- XYLOSE 

COH  COH 

H.C.OH  H.C.OH. 

OH.C.H  OH.C.H. 


H.C.OH  H.C.OH 

H.C.OH  H.C.OH 

COOH  H 


+  C02 


Literature  upon  Oxaluria:   A.  Magnus-Levy,  Bd.,  1,  155-159,  1906. 
21 


322  GLYCURONIC  ACID 

Occurrence  of  Glycuronic  Acid  in  the  Body. — As  for  the 
occurence  of  compounds  of  glycuronic  acid  in  the  economy, 
this  substance  has  been  recognized  by  C.  Neuberg  and  Paul 
Meyer  and  by  Lepine  and  Boulud,  as  a  normal  constituent  of 
the  urine  and  of  the  blood,  although  apparently  no  notable 
amounts  are  apt  to  accumulate  in  the  tissues  generally.55 
According  to  the  opinion  of  the  last-named  authors  the 
increment  in  reducing  power  of  blood  extracts  after  hydro- 
lytic  cleavage  ("sucre  virtue!")  may  at  least  partly  be 
referred  to  glycuronic  acid  compounds  supposed  to  be  pres- 
ent especially  in  the  formed  elements  of  the  blood.56 

Importance  of  Glycuronic  Acid  in  Diagnosis  of  Intestinal 
Disturbances  and  Diseases  of  the  Liver. — Excretion  of  gly- 
curonic acid  in  the  urine  apparently  depends  primarily 
upon  digestive  conditions  and  intestinal  putrefaction,  and 
thereafter  upon  the  quantities  of  indol  and  phenol  available 
for  conjugation.  According  to  E.  Mayerhofer's  studies  a 
new  reaction,  originated  by  Guido  Goldschmiedt  {v.  infra), 
producing  a  green  color  from  the  action  of  a-naphthol  and 
concentrated  sulphuric  acid  upon  glycuronic  acid,  is  in  gen- 
eral the  most  delicate  mode  of  detecting  the  presence  of 
intestinal  disturbances  in  infants.  While  the  test  is  in- 
variably negative  in  well  nourished  breast-fed  children,  it  is 
sufficiently  delicate  to  give  a  positive  result  with  even  the 
slightest  nutritive  disturbances  with  an  associated  height- 
ening of  intestinal  putrefaction,  the  intensity  of  color  in- 
creasing and  decreasing  with  the  grade  of  the  affection.  In 
artificially  fed  infants,  who  are  practically  never  free,  as  is 
known,    from    nutritive    disturbances,     the    absence     of 

55  Literature  upon  the  Occurrence  of  Glycuronic  Acid  Compounds  in  the 
Body:    C.  Neuberg,  Handb.  d.  Pathol,  d.  Stoffw.,  2,  226,  1907. 

68  R.  Lupine  and  Boulud,  Compt  Rendu,  1^1,  453,  1905,  and  earlier  con- 
tributions;   Jour,  de  Physiol.,  7,  775,  1905. 


DETECTION  OF  GLYCURONIC  ACID  323 

glycuronic  acid  excretion  in  the  nrine  is  really  an 
exception.57 

Apparently,  however,  urinary  glycuronic  acid  presents 
a  practical  clinical  interest  in  another  direction.  Studies  by 
K.  v.  Stejskal  and  Grünwald  58  have  indicated  that,  while  the 
normal  body  tends  to  carry  out  the  synthesis  of  conjugate 
glycuronic  acid  after  administration  of  camphor  with  such 
precision  that  almost  the  whole  quantity  of  camphor- 
giycuronic  acid,  as  calculated  theoretically,  appears  in  the 
urine  in  the  course  of  twenty-four  hours,  in  a  patient  suf- 
fering from  hepatic  cirrhosis  or  severe  catarrhal  jaundice, 
the  process  is  distinctly  inhibited.  The  expectation  of  pos- 
sible employment  of  the  synthetic  production  of  this  sub- 
stance as  the  basis  for  a  method  of  functional  hepatic 
diagnosis  is  apparently,  therefore,  not  entirely  without  rea- 
son, although  there  is  not  the  least  reason  for  referring  the 
processes  of  glycuronic  acid  formation  exclusively  to  the 
liver.  It  has  been  shown,  however,  in  studies  carried  on  in 
Hofmeister  's  laboratory,59  that  hepatic  destruction  from 
acid  infusion  may  be  without  any  influence  upon  the  syn- 
thesis of  glycuronic  acid  after  administration  of  chloral; 
and  J.  Pohl 60  has  found  that  severe  hepatic  changes  due  to 
intoxication  with  ethylendiamine  inhibit,  it  is  true,  the 
formation  of  urochloralic  acid,  but  do  not  inhibit  that  of 
phenol-glycuronic  acid. 

Detection  and  Estimation  of  Glycuronic  Acid. — In  conclu- 
sion a  few  words  may  be  devoted  to  discussion  of  the  modes 
of  detection  and  estimation  of  glycuronic  acid. 

57  B.  von  Fenyvessy  (Pharmakol.  Instit.,  Budapesth),  Arch,  internat.  des 
Pharmacodyn,  12,  407,  1903;  C.  Tollens  and  F.  Stern,  Zeitschr.  f.  physiol. 
Chem.,  64,  39,  1910;  C.  Tollens,  ibid.,  67,  138,  1910;  E.  Mayerhofer  (Franz 
Josef's  Hospital,  Vienna),  Zeitschr.  f.  Kinderheilk.,  1,  226,  1910;  Zeitschr.  f. 
physiol.  Chem.,  10,  391,  1910. 

58 K.  v.  Stejskal  and  H.  Fr.  Grünwald  (Second  Med.  Clinic,  Vienna),  Wiener 
klin.  Wochenschr.,  1909,  No.  30. 

59  F.  Pick  ( Hofmeister's  Lab.,  Prague),  Arch.  f.  exper.  Pathol.,  33,  315, 
1894. 

00  J.  Pohl   (Prague),  Arch.  f.  exper.  Pathol.,  41,  971,  1895. 


324       •  GLYCURONIC  ACID 

In  a  general  way  we  may  suspect  a  given  urine  of  con- 
taining conjugate  glycuronic  acid  if  it  polarizes  to  the  left 
without  showing  fermentescibility  and  reducing  power,  the 
lasvogyratory  power  changing  to  dextrogyratory  and  coin- 
cidently  a  marked  reducing  power  developing  after  boiling 
for  a  long  time  with  dilute  acid. 

C.  Neuberg  recommends  in  the  determination  of  glycur- 
onic acid  to  first  concentrate  it  by  lead  precipitation,  after 
hydrolytic  cleavage  of  the  urine.  After  decomposing  the 
lead  precipitate  by  means  of  sulphuretted  hydrogen  or  sul- 
phuric acid  one  sometimes  succeeds  in  obtaining  the  beau- 
tiful crystalline  cinchonin  salt  of  the  acid.  The  p-brom- 
phenylhydrazine  compound  of  glycuronic  acid  may  also 
prove  of  important  service,  according  to  Neuberg ;  it  can  be 
distinguished  from  the  bromphenylosazones  of  sugar  by  its 
almost  complete  insolubility  in  warm  alcohol,  but  is  espe- 
cially characterized  by  the  fact  that  its  optical  rotating 
power  in  a  pyridinalcoholic  solution  is  much  more  marked 
than  that  of  any  of  the  analogous  sugar  compounds. 

The  brilliant  colors  produced  in  the  orcin-  and  phloro- 
glucin-tests  may  also  serve  for  the  detection  of  glycuronic 
acid.  According  to  Neuberg,  these  tests  are  not  to  be  at- 
tributed to  the  separation  of  furfurol,  and  to  speak  of  them 
as  ' '  furfurol  reactions  "  is  a  mistake.  They  are,  however, 
not  at  all  characteristic  of  glycuronic  acid,  but  are  well 
known  reactions  also  of  the  pentoses.  It  seems,  moreover, 
that  they  respond  to  any  sugar  with  an  uneven  number  of 
carbon  atoms  in  its  molecule. 

The  naphtho -res orcin  reaction  of  B.  Tollens  61  offers  dis- 
tinct advantages  over  these  reactions.  It  depends  on  the 
fact  that  naphtho-resorcin  [1.3  dioxynaphthalin,  C10HG 
(OH)2]  changes  the  glycuronic  acid,  on  boiling  with  hydro- 

81 B.  Tollens  (Göttingen),  Ber.  d.  deutsch,  ehem.  Ges.,  41,  1783,  1908; 
Zeitschr.  f.  physiol.  Chem.,  56,  115,  1908;  C.  Tollens  (Kiel),  Münchener  med. 
Wochenschr.,  1909,  652;  C.  Neuberg  and  0.  Schewket,  Biochem.  Zeitschr.,  44, 
502,  1912. 


DETECTION  OF  GLYCURONIC  ACID  325 

chloric  acid,  into  a  coloring  matter  which  gives  a  blue  color 
in  ether,  and  in  solution  gives  a  dark  spectral  band  in  the 
vicinity  of  the  sodium  lime.  It  is  true  that  this  reaction  is 
also  not  specific  for  glycuronic  acid ;  it  occurs  also  (as  shown 
by  A.   Mandel   and   C.   Neuberg)62   with   many   aliphatic 

CO 

aldehyde-  and  ketonic-acids  containing  the  group       | 

COH 

beginning  with  glyoxylic  acid,      |  ,  and  seems  to  be  due 

COOH 

to  a  certain  combination  between  carboxyl  and  carbonyl 

groups.    Indoxyl  may  also  cause  confusion.63     The  test  is 

suited,  however,  for  positive  differentiation  of  glycuronic 

acid  from  the  pentoses.     If  glycuronic  acid  in  a  mixture  of 

different  sugars  is  precipitated  with  these  as  an  osazone,  the 

glycuronic  acid  osazone  alone  will  give  the  Tollens  color 

reaction.64 

A  very  valuable  recent  reaction  for  glycuronic  acid  has 
been  originated  by  Guido  Goldschmiedt,  as  above  stated ;  he 
found  that  glycuronic  acid  with  a-naphthol  and  concentrated 
sulphuric  acid  will  give  an  emerald  green  color  (passing  into 
violet  and  blue  when  diluted  with  water).  Neither  hexoses 
nor  pentoses  give  this  reaction,  which  is  directly  applicable 
in  human  urine  only  when  the  diet  is  free  from  nitrates  (as 
milk,  white  bread  and  meat) .  The  urine  of  dogs  and  rabbits 
is  always  free  from  nitrites,  as  proved  by  the  diphenylamine 
reaction.65 

A  method  of  quantitative  determination  of  glycuronic 
acid  has  been  recently  proposed  by  Lefevre  and  Tollens.  It 
depends  on  the  fact  that  if  urine  is  precipitated  by  acetate 
of  lead  and  ammonia,  the  furfurol  appearing  in  distillation 

62  A.  Mandel  and  C.  Neuberg,  Biochem.  Zeitschr.,  13,  148,  1908;  C.  Neuberg, 
ibid.,  24,  436,  1910. 

"R.  Bernier,  Jour.  d.  Pharm,  et  de  Chim.,  series  7,  2,  401,  1910;  cited  in 
Jahresber.  f.  Tierchem.,  40,  301,  1910. 

84  C.  Neuberg,  and  S.  Saneyoshi,  Biochem.  Zeitschr.,  36,  56,  1911. 

66  G.  Goldschmiedt  (Prague),  Zeitschr.  f.  physiol.  Chem.,  65,  389,  1910; 
67,  194,  1910;  cf.  also  L.  v.  Udränsky,  ibid.,  68,  88,  1910. 


326  GLYCURONIC  ACID 

of  this  precipitate  with  acids  has  its  actual  source  in  glycu- 
ronic  acid.  A  molecule  of  the  latter  breaks  down  into  a 
molecule  of  furfurol  and  C02.  The  former  may  be  weighed 
after  precipitation  of  the  distillate  with  phloroglucin ;  and 
the  C02  taken  up  in  a  potash  apparatus  and  estimated.  As 
furfurol  formation  is  also  possible  from  the  pentoses,  but 
the  accompanying  separation  of  carbonic  acid  is  entirely 
characteristic  for  glycuronic  acid  (from  the  carboxylic 
group  of  which  it  arises)  the  method  serves  to  determine 
glycuronic  acid  in  the  presence  of  pentoses.66  It  is  to  be 
expected  now  that  we  possess  this  method,  our  knowledge 
of  the  role  and  significance  of  glycuronic  acid  in  the  economy 
will  advance  more  rapidly  than  has  hitherto  been  the  case. 

66  B.  Tollens,   Zeitschr.   f.   physiol.   Chem.,   61,  95,    1909;    U.  Lefevre  and 
B.  Tollens,  Ber.  d.  deutsch,  chem.  Ges.,  Jf0,  4513,  1908. 


CHAPTER  XIV 
SUGAR  DESTRUCTION  IN  THE   ECONOMY 

Glycolysis. — The  author  feels  that  it  is  desirable  to  con- 
clude the  series  of  lectures  upon  the  question  of  carbohydrate 
metabolism  by  a  statement  of  the  problem  of  glycolysis. 
Although  the  ground  is  by  no  means  sure  and  we  know 
perfectly  well  that  whatever  is  to  be  said  is  far  more  of  a 
negative  than  of  positive  import,  the  question  cannot  well  be 
neglected  from  the  list  of  important  problems  of  physio- 
logical chemistry — how  the  economy  proceeds  in  the  cata- 
bolism  of  sugar. 

Efforts  to  discover  the  answer  of  this  problem  reach 
rather  far  back.  It  is,  of  course,  quite  natural  that  in  part 
these  took  inception  in  an  example  of  glycolysis  in  nature,  a 
process  which  has  achieved  a  tremendous  economical  im- 
portance (not  exactly  to  the  best  interest  of  human  welfare), 
that  of  alcoholic  fermentation  of  sugar  by  yeast  fungi.  It  is 
entirely  apropos  to  inquire  whether  other  animal  and 
vegetable  cells  may  not  have  in  some  degree  a  power  similar 
to  that  of  the  yeasts  to  split  sugar  into  alcohol  and  C02. 

Distribution  of  Zymases  in  the  Vegetable  Kingdom. — Al- 
though Pasteur  and  Pfeffer  had  originally  suggested  that 
the  first  phase  of  the  decomposition  of  sugar  in  plants  con- 
sists of  an  anaerobic  formation  of  alcohol  which  then  under- 
goes combustion  into  C02  and  water  upon  the  access  of  oxy- 
gen, Stoklasa,  of  Prague,  the  biochemist,  and  his  pupils  de- 
serve the  credit  of  first  having  experimentally  furnished 
support  for  the  idea.  After  E.  Buchner  in  the  latter  part  of 
the  nineties  made  the  important  discovery  that  an  enzyme 
elaborated  by  the  vital  activity  of  the  yeast  cells,  zymase,  is 
capable  of  setting  up  fermentation  of  sugar  into  alcohol  and 
carbonic  acid,  the  basis  was  prepared  for  the  recognition  of 
the  zymases  of  higher  types  of  living  beings.  By  employing 
the  methods  used  by  Büchner  for  recovering  the  zymase  of 

327 


328  SUGAR  DESTRUCTION  IN  THE  ECONOMY 

yeast  Stoklasa  and  his  collaborators  succeeded  (by  precipi- 
tating expressed  juices  by  alcoholic  ether  and  rapidly  drying 
the  precipitate)  in  obtaining  zymases  from  beets,  potatoes, 
peas  and  green  types  of  plants,  i.e.,  enzymes  capable  of  in- 
ducing an  active  fermentation  of  sugar  into  alcohol  and  car- 
bonic acid  in  complete  absence  of  microorganisms.1  The 
studies  of  Palladin  and  Kostytschew  mark  a  further  step, 
showing  that  the  anaerobic  respiration  of  plants  is  appar- 
ently at  least  in  part  an  alcohol  fermentation  which  inde- 
pendently of  the  life  of  the  cells  takes  place  from  the  influ- 
ence of  enzymes  even  after  the  cells  have  been  killed  by 
freezing.  Besides  the  zymases,  according  to  Stoklasa  there 
are  held  to  be  also  "  lactolases' '  concerned  in  the  anaerobic 
plant  respiration,  which  give  rise  to  formation  of  lactic  acid. 
The  related  older  view,  that  a  molecule  of  sugar  is  first 
separated  into  two  molecules  of  lactic  acid  and  these  later 
fermented  into  alcohol  and  carbonic  acid,  can  no  longer  be 
regarded  as  correct  from  the  modern  viewpoint  of  the  fer- 
mentation theory.  However,  lactic  acid  can  originate  from 
labile  intermediate  products  through  transposition  proc- 
esses. In  the  later  stages  of  the  fermentation  process  the 
alcohol  fermentation  (the  zymase  being  injuied  by  the  ad- 
vancing acidity)  may  lag  behind  the  lactic  acid  fermenta- 
tion, and  in  still  later  phases  the  latter  may  in  turn  be 
limited  by  a  butyric  acid  fermentation. 

Supposed  Occurrence  of  Zymases  in  Animal  Tissues. — 
There  is  thus  no  ground  for  question  as  to  the  occurrence 
of  an  alcohol  fermentation  in  the  anaerobic  respiration  of 
plants.  Stoklasa,  however,  believed  his  findings  applicable 
to  the  field  of  the  animal  economy,  and  thought  that  he  could 
recover  zymases  from  all  sorts  of  tissue  (muscle,  liver,  pan- 
creas, leucocytes,  etc.).2  These  latter  discoveries,  which 
were  subjected  to  control  tests  by  many  authors,  have,  how- 

1  Literature  upon  the  Zymases  of  Higher  Plants :  C.  Oppenheimer,  Die 
Fermente,  3d  ed.,  466-474,  193  0. 

2  Cf.  Literature:    E.  Abderhalden,  Lehrb.  d.  physiol.  Chem.,  2d  ed.,  89,  1909. 


ZYMASES  IN  ANIMAL  TISSUES  329 

ever,  been  confirmed  only  here  and  there,3  but  have  for  the 
most  part  excited  opposition. 

Thus  Blumenthal  and  others  found  that  sugar  catabolism 
proceeds  in  the  tissues  with  formation  of  C02,  it  is  true,  but 
not  with  a  corresponding  production  of  alcohol.4  Small 
amounts  of  alcohol  have  actually  been  found  in  animal  tis- 
sues by  various  observers,5  but  Landsberg  believes  this  can 
be  fully  explained  as  the  result  of  absorption  of  alcohol  from 
the  gastroenteric  canal,  where  from  the  influence  of  yeasts 
and  bacteria  upon  the  carbohydrates  there  is  always  oppor- 
tunity given  for  alcohol  production.  Then,  too,  it  has  been 
shown  that  only  the  putrefaction  of  tissues,  not  their  auto- 
lysis, increases  their  alcohol  content.  Battelli  maintained 
the  circulation  in  freshly  killed  animals  for  two  hours  by 
compressing  the  exposed  heart,  and  coincidently  kept  up 
artificial  hydrogen  respiration  through  a  tracheal  canula; 
under  which  circumstances  it  was  shown  that  in  the  absence 
of  oxygen  the  economy  of  the  higher  animals  does  not  form 
carbonic  acid,  that,  as  a  matter  of  fact,  therefore,  there 
apparently  does  not  exist  here  an  " anaerobic  respiration." 6 
It  is  certainly  worth  considering,  too,  that  in  the  anoxybiosis 
of  ascarides  and  earth  worms,  as  shown  by  the  studies  of 
Weinland  and  Lesser,  there  is  nothing  in  the  way  of  an 
alcoholic  fermentation  of  sugar  (in  these,  however,  as  an 
important  product  of  carbohydrate  cleavage  there  is  formed, 
besides  carbonic,  a  volatile  fatty  acid,  apparently  valerianic 
acid).7  The  most  weighty  objection  to  Stoklasa's  idea, 
however,  is  to  be  seen  in  the  circumstance  that  many  careful 

3R.  Robert,  Pflüger's  Arch.,  99,  176,  1909;  F.  Maignan,  Compt.  Rend.,  140, 
1063,  1124,  1905;    F.  Ransom  (Cambridge),  Jour,  of  Physiol.,  40,  1,  1910. 

4  F.  Blumenthal,  Deutsch,  med.  Wochenschr.,  1903,  No.  51;  J.  Feinschmidt 
(F.   Blumenthal's  Lab.),   Hofmeister's   Beitr.,   4,   511,    1904;     E.   Bendix    (F. 

Blumenthal's  Lab.),  Zeitschr.  f.  physik.  und  diät.  Ther.,  2,  218,  1899. 

5  Ford ;  Rajewski ;  G.  Landsberg,  Zeitschr.  f.  physiol.  Chem.,  41,  505,  1904 ; 
Reach  (A.  Durig's  Lab.),  Biochem.  Zeitschr.,  3,  326,  1907. 

8  F.  Battelli,  Arch,  intern,  de  Physiol.,  1,  47,  1904. 

T  Literature  upon  Anoxybiosis:  E.  J.  Lesser,  Ergebn.  d.  Physiol.,  8,  742- 
796.  1909 ;    Zeitschr.  f.  Biol.,  52,  282,  1909. 


330  SUGAR  DESTRUCTION  IN  THE  ECONOMY 

observers,8  in  their  control  tests  of  his  statements  (with 
provision  of  thorough  asepsis),  failed  to  obtain  any  fermen- 
tation. "The  fact,"  states  Vernon,9  "that  Stoklasa  and 
his  collaborators  were  unable  to  find  any  bacteria  by  their 
cultures  does  not  necessarily  prove  that  they  were  not  pres- 
ent. As  far  as  can  be  made  out  from  their  studies  the 
cultures,  as  a  rule,  were  placed  in  aerobic  surroundings,  al- 
though the  fermentations  were  anaerobic.  The  cultural  con- 
ditions were,  therefore,  not  favorable  for  the  growth  of 
the  bacteria  which  occasion  the  alcoholic  fermentation." 
Harden  and  Maclean,10  who  have  recently  subjected  the  work 
of  Stoklasa  to  severe  criticism,  found  that  if  to  solutions 
of  glucose  they  add  tissue  juices,  or  sediments  obtained 
therefrom  by  alcoholic  ether,  in  the  course  of  the  first  few 
hours  a  very  trivial  gas  development  takes  place,  the  cause 
of  which  is  purely  physical,  and  which  is  noticeable  both 
when  there  is  no  sugar  present  and  when  disinfectants 
are  added.  Later  on,  however,  a  gas  production  begins, 
continuously  increasing  in  intensity,  which  goes  on  in  pro- 
portion to  the  growth  of  bacteria.  If  toluol  be  added  in 
quantities  which  are  harmful  to  bacteria  but  which  are 
known  from  experience  to  be  without  influence  upon  the 
zymases,  the  gas  formation  ceases.  That  the  test  for  bac- 
teria in  Stoklasa's  experiments  so  frequently  resulted  nega- 
tively, may,  in  the  opinion  of  these  authors,  have  been  due 
to  the  fact  that  it  was  made  at  the  end  of  the  fermentation, 
therefore  at  a  time  when  the  bacteria  may  have  been  al- 
ready destroyed  by  the  concentration  of  their  own  metab- 
olic products  (alcohol,  lactic  acid). 

However  highly  Stoklasa's  discoveries  as  to  the  impor- 
tance of  zymases  in  the  anasrobic  respiration  of  plants  may 
be  regarded,  it  must  be  said  that  analogous  processes  in  the 

s  Battelli,  Maze,  Portier,  Colmheim,  Embden,  Arnheim  and  Rosenbaum, 
Harden  and  Maclean. 

9H.  M.  Vernon,  Ergebn.  d.  Physiol.,  9,  205,  1910. 

10  A.  Harden  and  H.  Maclean  (Lister  Instit.),  Jour,  of  Physiol.,  42,  64,  1911. 


ZYMASES  IN  ANIMAL  TISSUES  331 

animal  economy  have  not  only  not  been  proved  but  are  not 
even  probable. 

The  author  acknowledges  that  this  is  only  his  own  sub- 
jective impression,  and  desires  to  add  that  others  who  have 
gone  at  length  into  this  problem  have  arrived  at  a  contrary 
opinion.  Thus  Carl  Oppenheimer  does  not  look  on  the  bac- 
terial objection,  even  if  it  cannot  be  completely  put  aside,  as 
the  real  nucleus  of  the  question.  "Stoklasa  found  a  satis- 
factory reproduction  of  yeast  fermentation  in  all  its  phases. 
Where  are  the  bacteria  which  are  carrying  this  on?  We  are 
aware,  of  course,  that  in  bacterial  fermentations  alcohol 
occurs  as  a  more  or  less  insignificant  by-product.  Either 
Stoklasa's  alcohol  findings  are  false — when  there  is  nothing 
further  to  be  said  to  the  contrary ;  or  they  are  correct — and 
in  this  case  they  cannot  be  referred  to  the  action  of  bacteria. 
That  true  yeast  cells  are  present  in  Stoklasa's  ether-precipi- 
tated extracts  of  tissues  no  one  has,  to  the  best  of  my  knowl- 
edge, as  yet  asserted.  A  priori  it  is  much  more  probable 
that  the  investigators  following  Stoklasa  have  not  had  the 
same  fortunate  hand  as  he.  .  .  .  Other  sources  of  error 
are  in  all  probability  to  be  apprehended  in  the  antiseptics 
employed;  which  perhaps  may  have  so  thoroughly  elimi- 
nated the  bacteria  so  often  called  into  question  that  the  easily 
affected  zymase  has  also  been  destroyed  by  them.  .  .  . 
We  have,  in  fact,  here  one  of  the  most  curious  of  spectacles, 
one  which  only  an  exact  research  can  afford — on  one  side  a 
series  of  experiments  published  in  fullest  extent,  with  all 
details,  which  always  give  the  same  result;  on  the  other, 
a  list  of  reinvestigators  who  are  unable  to  find  anything  and 
who  introduce  into  the  field  unsupported  contradiction  of 
the  experiments.  As  long  as  no  one  appears  to  show 
.  .  .  where  the  alcohol  and  lactic  acid  come  from  in 
Stoklasa's  experiments  his  experiments  are  going  to  stand 
like  a  rocher  de  bronze.'''' 

Even  as  objective  an  observer  as  Hammersten11  con- 

11  O.  Hammersten,  Lehrb.  d.  physiol.  Chem.,  7th  ed,  382,  1910. 


332  SUGAR  DESTRUCTION  IN  THE  ECONOMY 

eludes  that  the  statements  of  Stoklasa  and  his  collaborators 
have  not  been  controverted,  and  believes  that  we  cannot 
deny  the  possibility  that  an  alcoholic  fermentation  can  exist 
in  animal  tissues  as  well  as  in  plant  tissues  in  anaerobic 
respiration. 

Here  again  is  an  example  of  how  differently  a  given 
situation  may  strike  the  minds  of  different  individuals. 

The  same  impression  will  be  aroused  when  we  attempt 
to  discuss  what  is  thought  to  be  known  of  the  glycolytic 
power  of  ground-up  tissues  and  the  expressed  juices  of 
tissues. 

Cohnheim's  Pancreas-Muscle  Experiment. — In  view  of 
the  importance  to  be  attributed  to  the  pancreas  in  carbohy- 
drate metabolism  since  the  discovery  of  pancreatic  diabetes, 
it  was  desirable  to  determine  whether  a  special  extracorpor- 
eal glycolytic  power  is  inherent  to  the  pancreas.  Otto  Cohn- 
heim  believes  that  this  may  be  answered  affirmatively,  in 
the  sense  that  the  muscles  contain  a  glycolytic  ferment  which 
owes  its  activation  to  the  pancreas.  The  "  pancreatic  acti- 
vator" is  believed  to  be  a  thermostable  substance,  soluble 
in  dilute  alcohol,  the  effect  of  which  in  increasing  amounts 
is  peculiar,  first  increasing  and  then  diminishing.  Cohn- 
heim  compares  this  last  with  the  phenomena  of  complement 
deviation  and  overfixation  in  the  combined  action  of 
amboceptor  and  complement.  In  extraction  of  the  glyco- 
lytic enzyme  of  the  muscle,  which  is  very  easily  affected  by 
salt  solutions,  an  ice-cold  solution  of  sodium  oxalate  is  re- 
commended. The  quantity  present  in  muscles  is  believed  to 
be  subject  to  marked  variation  even  in  physiological  condi- 
tions ;  thus  it  is  supposed  that  cat  muscle  is  strongly  active 
in  glycolysis  if  the  cats  have  been  fed  upon  milk  and  sugar, 
but  of  little  glycolytic  power  if  the  animals  are  fed  on  fat 
or  fatigued  from  physical  exercise.12 

13 O.  Cohnheim  (Heidelberg),  Zeitschr.  f.  physiol.  Chem.,  39,  396,  1903; 
1,2,  402,  1904;   J,3,  547,  1905;   47,  253,  1906. 


OBJECTIONS  OF  CLAUS  AND  EMBDEN  333 

Objections  of  Claus  and  Embden. — B.  Claus  and  G.  Emb- 
den  13  after  subjecting  Coknheim's  experiments  to  careful 
control  investigation,  came  to  believe  that  they  are  dealing 
with  an  action  due  to  contaminations,  probably  of  bacterial 
nature.  The  apparent  increase  of  glycolysis  on  addition  of 
pancreatic  material  might  possibly  be  due  to  nothing  more 
than  that  corpuscular  elements  may  withdraw  some  of  the 
toluol  from  the  fluid  saturated  with  this  substance,  and  in 
this  way  really  favor  the  development  of  bacteria.  The 
writers  named  also  express  the  opinion  that  toluol,  as  well 
as  other  antiseptics,  if  not  added  in  large  amounts  affords 
no  very  great  protection  against  bacteria,  and  that  the  com- 
mon method  of  studying  the  action  of  glycolytic  ferments 
in  tissue  pulp  with  antiseptics  added  is  not  a  serviceable  one 
and  should  be  abandoned. 

There  is  no  doubt  of  the  very  great  difficulty  of  entirely 
excluding  confusion  of  results  because  of  the  influence  of 
microorganisms  in  experiments  of  this  sort,  and  this  has 
been  confirmed  from  another  point  of  view.14  The  convic- 
tion is  borne  in  upon  us  that  even  if  we  do  not  employ  a 
tissue  pulp,  but  work  with  acetone-precipitates  from  the 
expressed  juices,  and  whether  toluol  or  chloroform  be  used 
as  an  antiseptic,  we  are  by  no  means  sure  of  not  finding 
scattered  bacteria  in  the  sediment.15 

However  impressed  the  writer  may  be  that  the  greatest 
scepticism  for  all  the  discoveries  in  this  field  is  apropos,  that 
moreover  many  of  them  are  merely  without  objection,  and 
that  especially  all  estimates  of  the  quantity  of  glycolytic 
enzyme  in  the  tissues  are  apparently  extremely  problem- 
atical, he  would  not  willingly  be  persuaded  that  everything 
which  has  been  observed  and  noted  here  is  actually  nothing 
but  the  effect  of  bacteria. 

UR.  Claus  and  G.  Embden  (Frankfurt  a.  M.),  Hofmeister's  Beitr.,  6,  214, 
343,  1905. 

14 G.  C.  E.  Simpson  (Liverpool),  Biochem.  Jour.,  5,  126,  1910. 

15  L.  Rapoport  (First  Med.  Clinic,  Berlin),  Zeitschr.  f.  klin.  Med.,  57,  208, 
1905. 


334  SUGAR  DESTRUCTION  IN  THE  ECONOMY 

No  great  importance  can  be  attributed  by  the  author  to 
experiments  with  tissue  pulp,10  as  the  technical  difficulties  of 
antiseptics  with  such  material  seem  at  the  present,  at  least, 
not  overcome.  The  author,  however,  acknowledges  an  im- 
pression that  it  may  be  a  mistake  to  set  aside  without  further 
consideration  as  ' '  the  effects  of  bacteria ' '  the  results  of  all 
experiments  upon  the  glycolytic  action  of  expressed  juices 
provided  they  are  conducted  with  necessary  antiseptic  pre- 
cautions. 

Possible  Existence  of  Glycolytic  Tissue  Ferments. — One 
should  remember,  for  instance,  that,  according  to  Fein- 
schmidt,17  in  the  expressed  juices  from  the  pancreas,  liver 
and  muscles,  even  in  the  presence  of  0.9  per  cent,  of  sodium 
fluoride,  appreciable  glycolysis,  with  development  of  C02 
and  organic  acids,  but  with  only  traces  of  alcohol,  is  said  to 
take  place.  It  is  without  doubt  of  importance,  too,  that 
Cohnheim  's  work  should  have  been  confirmed  by  the  Amer- 
ican, Hall,18  in  a  very  carefully  conducted  and  critical  con- 
trol experiment.  Hall  expressed  the  juice  from  muscle  and 
pancreas;  and  with  these  and  with  alcoholic  extracts  (by 
boiling)  from  the  latter,  mixed  or  separate,  acted  upon  a 
dilute  sugar  solution  at  incubator  temperature  and  in  pres- 
ence of  toluol,  the  length  of  the  experiment  not  exceeding 
three  days.  That  he  should  have  found  as  an  average  from 
his  experiments  that  pancreatic  juice  alone  destroyed  only 
0.3  per  cent,  of  the  amount  of  glucose  employed,  muscle  juice 
alone  only  1.6  per  cent.,  the  combination  of  muscle  juice  and 
pancreas  4.4  per  cent.,  but  the  combination  of  the  alcoholic 
extract  of  pancreas  and  muscle-juice  as  much  as  18.3  per 
cent.,  is  very  remarkable.  The  objection  that  such  results 
are  entirely  due  to  bacterial  influences  seems  decidedly  im- 

10 Literature:  (Blumenthal,  Ssobolew,  Herzog,  Feinschmidt,  Arnheim  and 
Rosenbaum,  Sehrt,  Rapoport,  Braunstein,  Simacek,  R.  Hirsch)  in  Rosenberg, 
Handb.  d.  Biochem.,  3',  253,   1910. 

17  Feinschmidt,  Hofmeister's  Beitr.,  4,  511,  1904. 

18  C.  W.  Hall  (Harvard  Medical  School),  Amer.  Jour,  of  Physiol.,  18, 
283,  1907. 


GLYCOLYTIC  TISSUE  FERMENTS  335 

probable.  While  we  are  coming  to  recognize  from  a  grow- 
ing and  more  and  more  convincing  experience  that  even  with 
the  presence  of  toluol  it  is  not  at  all  easy  to  protect  a  tissue 
pulp  or  especially  suspensions  of  such  a  material  from 
bacterial  invasion  with  certainty,  we  have  no  reason,  as  far 
as  the  writer  is  aware,  to  doubt  the  efficiency  of  toluol  in  a 
fluid  medium.  Hall,  in  addition,  controlled  the  sterility  of  his 
tests  by  both  aarobic  and  anaerobic  culture  methods.  More- 
over the  fact  that  the  glycolytic  power  of  pancreatic  and 
muscle  extracts  failed  to  manifest  itself  upon  solutions  of 
fructose  and  lactose,  and  appeared  only  in  connection  with 
glucose,  specifically  contradicts  any  bacterial  influence,  bac- 
teria being  in  no  wise  selective  enough  to  make  such  a 
difference.19 

Recently  P.  A.  Levene,  who  has  at  his  disposal  the  great 
technical  facilities  of  the  Rockefeller  Institute,  of  New 
York,  has  investigated  the  glycolytic  influence  of  various 
animal  tissues  with  and  without  addition  of  "activators." 
The  tissues  as  such  proved  in  practically  all  cases  inactive. 
Addition  of  pancreatic  extract  to  muscle  was  without  effect 
in  case  of  canine  tissues,  in  rabbit  tissues  resulted  in  show- 
ing a  lowered  reducing  power  of  the  sugar  solutions  (but, 
in  the  dog,  for  example,  splenic  extract  in  combination  with 
other  tissues  seemed  to  be  feebly  active).  Levene 's  experi- 
ments have  shown,  however,  that  we  are  not  justified  in 
regarding  a  loss  in  reducing  power  of  the  glucose  solutions 
employed  as  due  only  to  "glycolysis."  It  seems  that  con- 
densation processes,  converting  simple  sugar  to  higher 
molecular  products,  may  be  involved.  The  reducing  power 
of  a  sugar  solution  which  has  been  lowered  by  the  combined 

19Stoklasa,  Zeitschr.  f.  physiol.  Chem.,  62,  35,  1909,  found  precisely  the 
opposite,  viz.,  that  preparations  made  from  pancreas  juice  by  alcoholic  ether 
would  break  up  disaccharides  in  the  absence  of  antiseptics,  with  formation  of 
lactic  acid,  alcohol  and  carbonic  acid.  However,  hexoses  apparently  ferment 
only  when  produced  by  fermentation  hydrolysis.  All  these  effects  are  decidedly 
interfered  with  by  the  presence  of  antiseptics.  Here,  too,  may  be  applied  the 
remark  that  bacteria  do  not  tend  to  be  very  selective  which  if  correct  to  one 
is  fair  to  the  other  side. 


336  SUGAR  DESTRUCTION  IN  THE  ECONOMY 

influences  of  muscle  plasma  and  pancreatic  extract,  can  be 
restored  by  boiling  with,  weak  hydrochloric  acid.  Levene 
also  succeeded  in  recovering  from  such  a  solution  the 
osazone  of  a  disaccharide.20 

What  now,  in  conclusion,  is  the  exact  meaning  of  this 
long  disquisition  ?  No  one  doubts  in  the  least  that  glycolysis 
takes  place  in  the  tissues  and  that  the  living  tissues  are  able 
to  catabolize  sugar.  The  point  in  question  is,  however, 
whether  we  are  in  position  to  reproduce  the  process  with 
dead  fragments  of  tissue  and  tissue  extracts,  whether  in  such 
case  we  are  justified  in  referring  the  glycolysis  to  the  influ- 
ence of  ferments  which  can  operate  independently  of  the  liv- 
ing cells.  As  far  as  the  writer  sees,  the  question  cannot  at 
present  be  either  affirmed  or  denied  with  certainty;  and  it 
seems  not  improbable  that  under  proper  conditions  ferments 
can  be  obtained  from  tissues  which  in  some  way  chemically 
change  the  sugar,  either  to  induce  cleavage  or  synthesis. 
But  that  is  probably  all  that  can  be  said.  For  the  assump- 
tion that  this  chemical  cleavage  is  to  be  regarded  as 
analogous  to  the  vital  combustion  of  sugar,  not  to  say 
equivalent,  there  is  in  the  writer's  opinion  not  the  least 
basis.  And,  too,  it  certainly  has  not  been  shown  that  the 
activity  of  Cohnheim's  pancreatic  activator  has  anything 
to  do  with  the  puzzling  influence  which  the  living  pancreas 
exercises  upon  the  metabolism  of  sugar.  If  Hall  {vide  sup.) 
found  that  alcoholic  extract  of  pancreas  is  more  efficient 
than  the  pancreas  itself,  and  if  Levene  found  the  pancreas 
inactive  in  many  cases,  but  did  find  an  extract  of  spleen 
to  be  active,  it  must  seem  that  an  unprejudiced  person 
would  conclude  that  they  are  perhaps  dealing  with  a  non- 
specific effect.  In  the  course  of  the  last  few  years  we  have 
heard  so  much  about  the  activating  influences  of  lipoids,  and 
especially  tissue  lipoids,  upon  the  processes  of  fermentation 
and  intoxication  of  the  most  varied  types,  that  one  may  well 

20  P.  A.  Levene  and  G.  M.  Meyer,  Jour,  of  Biol.  Chem.,  9,  97,  1911 ;    11,  347, 
353,  1912. 


EXPERIMENTS  UPON  SURVIVING  TISSUES         337 

consider  the  possibility  of  a  relation  with  such  substances  of 
the  rather  inconstant  effects  of  the  activators  which  Cohn- 
heim  and  his  followers  have  noted. 

All  in  all  the  writer  believes  that  the  expectation  of 
nearer  approach  to  the  secret  of  sugar  catabolism  in  the 
living  body  by  experiments  upon  tissue  pulp  and  expressed 
juices  is  at  the  present  unfortunately  decidedly  depressed. 
It  was  both  logical  and  essential  in  forcing  the  path  along 
this  way  to  make  and  perseveringly  repeat  the  experiment. 
But  it  is  quite  as  logical  after  being  quite  convinced  of  the 
impracticability  of  this  route  of  approach  to  look  about  for 
other  paths  which  lead  further. 

Experiments  upon  Surviving  Tissues. — A  more  promis- 
ing way  is  apparently  to  be  found  in  perfusion  of  living 
organs  removed  from  the  body.  Occasion  has  been  taken 
in  a  previous  lecture  to  state  in  detail  the  fact  that  in 
R.  Gottlieb's  laboratory  and  elsewhere  it  has  been  found 
possible  to  measure  continuously  the  amount  of  sugar  used 
by  the  beating  mammalian  heart  artificially  perfused.  Ref- 
erence has  already  been  made,  too,  to  the  expectations  we 
are  justified  in  cherishing  for  the  pancreatic  problem  by  ap- 
plying the  fine  perfusion  methods  of  E.  H.  Starling.  Oppor- 
tunity may  be  taken  here,  moreover,  to  refer  to  the  important 
experiments  of  the  American,  McGuigan,  who  perfused  or- 
gans with  blood  diluted  with  Ringer-Locke  solution  and 
mixed  with  different  kinds  of  sugar,  and  then  calculated  the 
amount  of  sugar  consumed  (with  reference  to  the  amount 
of  glycogen  shown  before  and  after  perfusion) .  His  experi- 
ments show  that  living  muscles  are  able  to  induce  a  rapid 
combustion  of  dextrose,  laevulose  and  galactose,  but  not 
maltose,  and  that  this  is  true  to  a  greater  degree  when  the 
muscle  is  in  activity  than  when  at  rest.  However,  in  perfu- 
sion experiments  on  dead  muscles,  which,  of  course,  should 
always  offer  more  natural  and  more  favorable  experiment- 
conditions  than  a  ground-up  muscle  or  an  expressed  juice, 
22 


338  SUGAR  DESTRUCTION  IN  THE  ECONOMY 

scarcely  any  loss  of  sugar  could  be  determined.21  In  the 
last  count  there  will  be  nothing  left  to  do  but  to  accept  the 
same  verdict  in  the  sugar  problem  as  we  long  ago  arrived 
at  in  the  case  of  the  protein  question ;  that  the  secret  of  the 
process  is  hidden  within  the  living  cells  and  cannot  be  ex- 
tracted by  any  solvent.  The  hope  of  preparing  some  fer- 
ment solution  and  by  some  clever  manipulation  bring  about 
the  combustion  of  protein  at  40°  C.  into  carbonic  acid, 
ammonia  and  water  has  long  since  been  abandoned.  The 
same  thing  will  have  to  be  accepted  in  the  case  of  the  sugar 
problem.  It  is  the  same  in  science  as  in  life;  when  we  stop 
striving  for  the  unttainable  our  efforts  to  reach  the  attain- 
able are  pressed  forward  with  just  so  much  the  fresher 
courage. 

Glycolysis  in  Blood. — Interesting  results  in  relation  to 
glycolysis  may  be  expected  from  the  study  of  sugar  catabol- 
ism  in  blood.  This  is  the  more  noteworthy  because  for  a  long 
time  there  was  nothing  at  all  promising  in  view  from  this 
point  of  investigation. 

Claude  Bernard  observed  long  ago  that  the  sugar  content 
diminished  in  blood  on  standing  for  a  time,  and  expressed 
the  idea  that  this  was  perhaps  due  to  a  destr action  of  sugar 
with  formation  of  lactic  acid.  Later  blood  glycolysis  was 
made  the  subject  of  careful  investigation,  especially  by 
Lepine,  who  framed  a  new,  much  discussed  and  soon  aban- 
doned theory  of  diabetes  upon  the  fact  that  he  found  the 
phenomenon  decreased  in  diabetics  and  in  animals  deprived 
of  the  pancreas.  Lepine,  and  with  him  Arthus,  referred  the 
glycolytic  process  in  the  blood  to  the  leucocytes ;  the  latter 
was  disposed  to  recognize  it  as  a  postmortem  phenomenon 
related  with  the  disintegration  of  the  blood  corpuscles.22 


21  McGuigan  ( Washington  Univ.,  St.  Louis,  Mo. ) ,  Amer.  Jour,  of  Physiol., 
21,  334,  1908;  H.  McGuigan  and  C.  L.  von  Hess  (Northwestern  Univ.  Med. 
School),  ibid.,  30,  341,   1912. 

öCf.  the  Older  Literature  upon  Blood-glycolysis :  C.  Oppenheimer,  Die 
Fermente,  3d  ed.,  478,  1910. 


IMPORTANCE  OF  LEUCOCYTES  IN  GLYCOLYSIS  339 

In  recent  times  a  series  of  carefully  conducted  investiga- 
tions have  afforded  important  results  in  this  connection,  for 
which  we  are  indebted  to  A.  Slosse,  of  Brussels,  and  his 
collaborators,  J.  de  Meyer  and  E.  Vandeput.  Primarily 
these  show  that  aseptic  glycolysis  in  the  blood  is  not  an 
alcoholic  fermentation  (even  the  most  delicate  tests  indicate 
not  the  slightest  trace  of  either  alcohol-  or  carbonic  acid- 
formation).  The  catabolism  takes  place  in  a  much  more 
interesting  manner,  one  molecule  of  glucose  separating  into 
two  of  lactic  acid,  and  the  latter  in  turn  into  acetic  acid  and 
formic  acid.  From  the  formic  acid  very  small  quantities  of 
CO  can  be  produced.  Sugar  catabolism,  therefore,  accord- 
ing to  Slosse,  characteristically  follows  this  schema: 

Glucose 
Lactic  Acid  Lactic  Acid 

Acetic  Acid  Formic  Acid 

Carbon  Monoxide 

This,  as  will  be  referred  to  later,  presents  striking 
analogies  to  the  mode  of  decomposition  of  sugar  under  the 
influence  of  alkalies.23 

Importance  of  Leucocytes  in  Blood-glycolysis. — J.  de 
Meyer 24  suggests  that  in  the  formation  of  the  glycolytic 
blood  ferment  this  is  secreted  as  a  proferment  by  the 
leucocytes  and  that  this  is  then  activated  by  a  substance 
produced  by  the  islands  of  Langerhans  in  the  pancreas  (the 
latter,  then,  as  a  "substance  sensibilatrice"  or  amboceptor). 
E.  Vandeput  finds,  in  consonance  with  the  older  statements 
of  Lepine,  that  the  glycolytic  power  of  the  blood  of  dogs  is 
distinctly  reduced  after  removal  of  the  pancreas,  and  that 

aA.  Slosse  (Instit.  Solvay,  Brussels),  Arch,  internat.  de  Physiol.,  11,  153, 
1911. 

24  J.  de  Meyer  (Brussels),  Ann.  de  l'lnstit.  Pasteur,  22,  778,  1908;  Arch, 
intern,  de  Physiol.,  7,  317,  1909;  8,  204,  1909;  Centralbl.  f.  Physiol.,  23,  No. 
26,  1910;    cf.  therein  Literature. 


340  SUGAR  DESTRUCTION  IN  THE  ECONOMY 

the  addition  of  pancreatic  extract  restores  it.25  If  with 
these  findings  we  take  into  account  the  previously  described 
observations  of  E.  H.  Starling  (v.  sup.,  p.  256),  who  ob- 
served a  distinct  increase  of  the  amount  of  sugar  used  up 
by  artificially  perfused  hearts  of  depancreatized  animals 
after  addition  of  pancreatic  extract  to  the  perfused  blood, 
we  cannot  help  feeling  that  the  active  manifestation  of 
glycolytic  power  by  the  corpuscular  elements  of  the  blood 
is  no  more  than  an  isolated  example  of  what  is  really  a  gen- 
eral rule,  that  perhaps  every  living  cell  is  capable  of  decom- 
posing sugar  and  requires  in  carrying  out  this  function  the 
combined  influence  of  an  activator  secreted  into  the 
circulation  by  the  pancreas. 

However,  that  the  formed  elements  of  the  blood,  espe- 
cially the  leucocytes,  are  directly  connected  with  the  glyco- 
lytic processes  in  the  blood  cannot  well  be  doubted  from  the 
uniform  confirmation  of  numerous  investigators.  Thus 
Lepine  and  Boulud  refer  glycolysis  in  the  blood  (in  their 
estimation  not  only  the  " immediate"  but  the  "virtuelle" 
hsemic  sugar  as  well  should  be  included)  to  the  colorless 
blood  cells  which  in  this  point  are  of  decidedly  more  impor- 
tance than  the  red  cells.26  The  observations  of  Nadina 
Sieber  upon  a  glycolytic  ferment  in  the  blood  fibrin  may 
perhaps  be  related  with  the  white  corpuscles  in  the  fibrin.27 
P.  Bona  and  A.  Döblin  look  on  the  observation  that  even  a 
sparing  haemolysis  occasioned  by  addition  of  water  will  stop 
glycolysis  (while  dilution  with  Ringer's  solution  or  with 
physiological  salt  solution  has  no  influence  upon  it)  as  favor- 
ing the  idea  that  sugar  catabolism  in  the  blood  is  surely  not 
a  simple  oxidation  process,  being  seen  even  in  complete 
absence  of  oxygen,  and  is  connected  with  the  integrity  of 

28  E.  Vandeput  (Slosse's  Lab.,  Brussels),  Arch,  intern,  de  Physiol.,  9, 
293,  1910;   cf.  also  J.  Edelmann    (Odessa),  Biochem.  Zeitschr.,  1,0,  314,   1912. 

20  R.  Lepine  and  Boulud,  Jour,  de  Physiol.,  13,  353,  1911;  C.  R.  Soc.  de 
Biol.,  60,  901,  1906. 

27  N.  Sieber  (Petersburg),  Zeitschr.  f.  physiol.  Chem.,  1,1,,  560,  1905. 


SUGAR  CATABOLISM  FROM  ALKALI  341 

the  formed  elements.28  In  serum  they  could  recognize  no 
loss  of  sugar  or  only  a  very  slight  diminution.  The  recent 
observations  of  Levene,  of  the  Rockefeller  Institute,  of  New 
York,  are  also  of  special  importance  in  this  relation.  The 
latter  noted  that  solutions  of  glucose  under  the  influence  of 
leucocytes  lose  a  part  of  their  reducing  power  (and  this  is 
not  restored  by  boiling  with  a  mineral  acid,  and  is,  therefore, 
surely  not  the  result  of  a  simple  molecular  condensation). 
The  fact  that  a  neutral  reaction  was  maintained  in  this  ex- 
periment by  means  of  Henderson's  phosphate  mixture  is  of 
special  significance.  If  water  was  employed  instead  the 
effect  was  lost ;  addition  of  tuluol  also  proved  deleterious. 
Levene,  just  as  Slosse,  found  that  lactic  acid  appears  in  the 
catabolism  of  sugar.29 

Sugar  Catabolism  from  the  Influence  of  Alkali. — In  re- 
viewing the  foregoing  material  which,  in  spite  of  the  extent 
of  literature  devoted  to  it,  is  decidedly  inadequate,  and  in 
trying  to  obtain  a  picture  of  the  process  of  sugar  decomposi- 
tion in  the  living  body,  in  the  author's  opinion  the  above 
mentioned  observations  of  Slosse  upon  the  catabolism  of 
sugar  in  the  blood  stand  out  prominently. 

Slosse  very  properly  referred  to  the  analogies  which  his 
observations  suggested  to  the  behavior  of  sugar  under  mild 
influence  of  caustic  alkalies. 

Kiliani,  about  the  beginning  of  the  eighties  made  the 
development  of  lactic  acid  from  sugar  the  subject  of  careful 
investigation ;  Framm  30  later  on  observed  the  appearance 
of  aldehyde  and  of  formic  acid  when  air  is  passed  through 
alkaline  solutions  of  sugar.  Still  later  Buchner,  Meisen- 
heimer  and  Schade31  noted  that  if  they  allowed  a  solution 
of  sugar  in  dilute  caustic  soda  to  stand  for  some  weeks  or 

28  P.  Rona  and  A.  Döblin  (Krankenhaus  am  Urban,  Berlin),  Biochem. 
Zeitschr.,  82,  489,  1911. 

28  Levene  and  Meyer,  Jour,  of  Biol.  Chem.,  11,  301,  1912;  12,  265,  1912. 

30  F.  Framm  (0.  Nasse's  Lab.,  Rostock),  Pfliiger's  Arch.,  64,  587,  1896. 

81  Buchner,  Meisenheimer,  Schade,  Ber.  d.  deutsch,  chem.  Ges.,  88,  623, 
1905;  39,  4217,  1906;  41,  1009,  1908;  Schade,  Zeitschr.  f.  physikal.  Chem.,  57, 
1,  1906;    cited  in  Biochem.  Centralbl.,  5,  No.  2311. 


342         SUGAR  DESTRUCTION  IN  THE  ECONOMY 

months,  with  the  air  excluded,  half  or  more  would  be  trans- 
formed into  inactive  lactic  acid,  the  remainder  for  the  most 
part  into  polyoxyacids  (dioxybutyric  acid,  etc.),  with  only 
small  amounts  of  formic  acid,  carbonic  acid  and  alcohol 
appearing  along  with  the  latter.  According  to  J.  de 
Meyer  32  glucose  breaks  up  in  soda  lye  in  the  presence  of 
platinum  sponge  with  formation  of  lactic  acid,  formic  acid 
and  oxalic  acid,  without  the  appearance  of  alcohol  and 
carbonic  acid.  However,  Jolles 33  saw,  when  he  allowed  the 
alkaline  cleavage  to  proceed  in  the  presence  of  oxidizing 
agents,  as  peroxide  of  hydrogen  and  silver  oxide,  at  the  body 
temperature,  only  formic  acid  develop  in  any  important 
quantity. 

That  sugar  can  undergo  extensive  catabolism  from  the 
influence  of  dilute  alkalies  even  at  the  temperature  of  the 
body  cannot  be  doubted.  There  is  a  question,  however, 
whether  the  degree  of  alkalinity  of  the  blood  and  of  the 
animal  juices  is  high  enough  to  permit  one  to  seriously 
consider  whether  this  mode  of  break-down  can  take  place 
physiologically.  In  view  of  a  result  obtained  by  Michaelis 
and  Bona34  in  a  fluid  containing  the  same  or  somewhat 
higher  amount  of  hydroxyl  ions  as  the  blood,  in  which  prac- 
tically no  sugar  catabolism  occurred  in  the  course  of 
twenty-four  hours  at  body  temperature  one  might  feel  dis- 
posed to  deny  off-hand  any  importance  to  this  factor. 

Importance  of  Catalyzers  in  the  Catalysis  of  Sugar. — As 
a  matter  of  fact,  however,  conditions  are  not  as  simple  as  this 
would  presuppose;  the  presence  of  catalyzing  agents  is 
certainly  a  matter  which  may  make  a  complete  difference. 
Thus  Walter  Lob  has  proved  that  in  salt-free  solutions  of 
sugar  of  the  same  degree  of  alkalinity  as  the  blood,  with  low 
concentration  of  hydroxyl  ions  (differing  very  slightly  from 


32  J.  de  Meyer,  Rev.  Med.  Memoirs  Lepine,  1911,  517,  cited  in  Centralbl.  f. 
d.  Ges.  Biol.,  12,  No.  2887. 

33  A.  Jolles,  Biochem.  Zeitschr.,  29,  152,  1910;    Centralbl.  f.  innere  Med., 
1911,  No.  1. 

84  L.  Michaelis  and  P.  Rona,  Biochem.  Zeitschr.,  23,  364,  1910. 


ELECTROLYTIC  CLEAVAGE  OF  SUGAR  343 

that  of  pure  water),  glycolysis  is  insignificant;  but  if  phos- 
phates be  added  a  very  appreciable  increase  takes  place.35 
The  same  author  also  makes  the  very  instructive  statement 
that  the  iron-containing  coloring  matter  of  the  blood,  in 
spite  of  its  unequivocal  peroxidase  character,  is  not  able  to 
affect  glucose  even  in  the  presence  of  peroxide  of  hydrogen ; 
while  substances  which  may  be  obtained  from  an  alcoholic 
extract  of  pancreas  when  treated  with  salts  of  iron,  effect  a 
marked  cleavage  of  sugar  in  which  (along  with  small  quanti- 
ties of  formic  acid,  polyoxyacids  and  carbonic  acid)  the  chief 
products  are  pentose  and  formaldehyde.36  Manganese  and 
potassium  are  also  capable  of  accelerating  alkali-hydrolysis 
of  sugar,  according  to  Slosse.37  It  is  without  question  not 
an  easy  matter  to  properly  judge  the  physiological  value  of 
such  observations ;  but  we  cannot  go  far  astray  in  assuming 
the  association  of  some  kind  of  catalyzing  agencies  in  the 
processes  of  sugar  cleavage  in  the  economy.  A  wide  and 
gratifying  field  of  research  in  physical  chemistry  is  opening 
in  this  connection. 

The  closely  related  question,  how  the  economy,  if  it  be 
capable  of  catabolizing  sugar  with  such  readiness,  should 
come  to  have  the  special  power  of  storing  up  large  reserves 
of  carbohydrate,  may,  perhaps,  in  the  opinion  of  Jolles,  be 
answered  by  supposing  that  glycogen,  because  it  does  not 
possess  free  aldehyde  groups,  is  acted  upon  with  much  more 
difficulty  than  sugar ;  and  that  in  this  manner  the  economy 
protects  the  dextrose  from  the  catabolizing  influence  of  the 
alkali  by  storing  it  as  glycogen  in  the  liver  and  muscles.38 

Electrolytic  Cleavage  of  Sugar. — Walter  Lob39  and,  inde- 
pendently, Carl  Neuberg,40  undoubtedly  followed  a  valuable 

85  W.  Lob  (Virchow  Krankenhaus,  Berlin),  Biochem.  Zeitschr.,  32,  43,  1911. 
35  W.  Lob  and  C.  Pulvermacher,  Biochem.  Zeitschr.,  29,  316,  1910. 
37  A.  Slosse,  Bull,  de  la  Soc.  Roy.  des  Sciences  m€d.,  Brussels,  May  5,  1911. 
S8A.  Jolles,  Wiener  med.  Wochenschr.,  1911,  No.  45. 
"W.  Lob,  Biochem.  Zeitschr.,  17,  132,  1909. 

40  C.  Neuberg,  in  association  with  L.  Scott  and  S.  Lachmann,  Biochem. 
Zeitschr.,  17,  270,  1909;   2>h  152,  1910. 


344        SUGAR  DESTRUCTION  IN  THE  ECONOMY 

line  of  thought  in  endeavoring,  by  studying  the  electrolysis 
of  different  sugars,  to  bring  out  analogies  to  the  physio- 
logical destruction  of  sugar  in  the  living  body.  Apparently 
formalydehyde  and  pentose  may  appear  as  stages  of  sugar 
cleavage  and  of  sugar  synthesis,  both  in  the  electrolytic 
reduction  of  grape-sugar  and  in  the  action  of  oxygen  on 
glucose.  We  are  probably  here  dealing  with  a  change  of 
equilibrium : 

GLUCOSE        PENTOSE   FORMALDEHYDE 

OH.,0»- ^OH.nOs  +  CH20. 

W.  Lob,  who  was  able  to  detect  in  the  electrolysis  of 
grape-sugar  in  dilute  sulphuric  acid  (using  lead  electrodes) 
gluconic  acid,  saccharic  acid,  arabinose,  arabonic  acid,  tri- 
oxyglutaric  acid,  formaldehyde  and  formic  acid,41  suggests 
the  following  schematic  plan  for  the  process : 

GLUCOSE        >■        ARABINOSE  -f-  FORMALDEHYDE 

C6H1206  C6H10O6  CH20 

j^      ^  j^      ^  /      \ 

CH2.OH         COOH  CH2.OH        COOH  H       CO, 

II  II  I 

(CH.OH),      (CH.OH),  (CH.OH)3     (CH.OH)3  COOH       CO 

COOH  COOH  COOH  COOH 

Gluconic  Acid    Sacchario  Acid        Arabonic  Acid    Trioxyglutaric  Acid  Formic  Acid. 

The  influence  of  ultraviolet  light  rays  is  also  followed  by 
cleavage  of  sugar  with  formation  of  aldehydes  and  volatile 
acids,  and  if  continued  may  lead  to  the  appearance  of 
formaldehyde  and  carbonic  acid.42 

Speaking  in  general  terms  it  can  be  readily  recognized 
that  we  have  not  progressed  in  the  study  of  the  catabolism 
of  sugar  in  the  economy  much  beyond  the  stage  of 
hypothesis.  As  it  is  well  known  that  everything  that  is 
printed  is  not  for  that  reason  true,  there  are  a  great  many 

41  Concerning  formic  acid  as  an  intermediate  product  in  sugar  cleavage  in 
the  body,  cf.  O.  Steppuhn,  and  H.  S'chellenbach,  Zeitschr.  f.  physiol.  Chem., 
80,  274,  1912. 

44  P.  Meyer  (Neuberg's  Lab.),  Biochem.  Zeitschr.,  32,  1,  1911;  A.  Jolles, 
ibid.,  33,  252,  1911;  H.  Bierry,  V.  Henri  and  Ranc,  Compt.  rend.,  152,  1629, 
1911,  and  earlier  contributions. 


ALCOHOLIC  FERMENTATION  OF  SUGAR  345 

publications  on  the  subject  which  the  writer  gladly  forbears 
to  inflict.  It  may  be  sufficient  to  refer  here  to  one  of  these 
only,43  that  of  Wohl:44 

Methylglyoxal  Lactic  Acid  Alcohol 

COH     COH     COH       COH       COOH       C02 
CH.OH   C.OH    CO        CO        CH.OH  — >     CH2(OH) 
CH.OH   CH      CH2        CH,        CH3         CH3 

— >•  — >■  — >■    Glycerine  Aldehyde  — >-  Methylglyoxal  Lactic  Acid 

CH.OH       CH.OH       CH.OH  COH  COH  COOH 

III                         I                        I  I 

CH.OH       CH.OH       CH.OH  CH.OH  CO >      CH.OH 

III  I  J.  1 

CH2OH       CH2.OH      CH2OH  CH2.OH  CH3  CH3. 

Mention  may  also  be  made  here  of  pyroracemic  acid 
(CHg.CO.COOH),  which,  according  to  Paul  Meyer,45  may 
be  placed  among  the  sugar-formers,  and  which,  according 
to  Neuberg,46  can  be  fermented  by  yeast  to  aldehyde  and 
carbonic  acid  (CH3.CO.COOH  =  CH3.COH  +  C02),  as  open 
to  consideration  as  a  possible  intermediate  stage  of  physi- 
ological sugar  catabolism. 

Mechanism  of  Alcoholic  Fermentation  of  Sugar. — It  was 
originally  thought  that  by  thorough  study  of  alcoholic  fer- 
mentation of  sugar  we  might  attain  definite  information  as 
to  the  catabolism  of  sugar  in  the  animal  economy.  The  fact, 
already  stated,  that  we  have  no  sound  support  for  the  as- 
sumption that  alcohol  formation  is  of  any  physiological 
importance  in  the  animal  body,  makes  the  value  of  studies  in 
this  line  of  questionable  worth.  Then,  too,  it  is  obvious  that 
it  is  impossible,  in  what  must  be  merely  a  brief  sketch  of  the 
subject  of  fermentation,  to  properly  deal  with  a  branch 
which  in  the  last  few  decades  has  grown  into  an  independent 
science.  The  only  thing  which  can  be  appropriately  done 
here  is  to  briefly  indicate  the  intermediate  stages,  as  we 

43  A.  Wohl  (Danzig),  Biochem.  Zeitschr.,  5,  54,  1907. 

44  Without  reference  to  the  stereochemical  configuration. 

"P.  Mayer  (C.  Neuberg's  Lab.),  Biochem.  Zeitschr.,  40,  441,  1912. 
40  C.  Neuberg,  Berlin,  physiol.  Ges.,  Nov.  1,  1912. 


346         SUGAR  DESTRUCTION  IN  THE  ECONOMY 

know  them  at  present,  which  are  of  the  most  importance 
in  the  transformation  of  sugar  into  alcohol  and  carbonic 
acid. 

At  first  many  thought  that  the  molecule  of  sugar  was 
primarily  separated  into  two  molecules  of  lactic  acid  in 
fermentation,  and  that  these  were  thereafter  broken  up  into 
alcohol  and  carbonic  acid: 

C6H1206  =  2C3H603 ;    C3H603  =  C2H5.OH  +  C02. 

We  know  that  lactic  acid  may  very  readily  be  broken 
down  to  form  acetaldehyde  and  formic  acid:  CH3.CHOH. 
COOH  ==  CH3.COH  +  H.COOH.  Euler,  of  Stockholm, 
noted  the  appearance  of  alcohol  and  carbonic  acid  after  sub- 
jecting lactic  acid  (or,  instead,  a  mixture  of  equal  amounts 
of  acetaldehyde  and  formic  acid)  to  the  influence  of  the 
ultraviolet  rays  of  a  uviol  lamp.47  However,  the  idea  that 
lactic  acid  is  an  intermediary  product  of  alcoholic  fermenta- 
tion was  in  time  abandoned.  Were  it  correct,  it  would  be 
necessary  to  suppose  the  lactic  acid  to  be  as  easily  fermented 
by  yeast  as  sugar,  or  even  more  easily.  This,  however,  is 
not  the  case;  in  fact,  when  lactic  acid  is  added  it  remains 
unaffected  by  the  fermentation.48 

Later  on  Eduard  Buchner  and  Jacob  Meisenheimer,49 
two  investigators  who  have  rendered  distinguished  service 
in  the  elucidation  of  the  fermentation  process,  were  disposed 

CH2.OH 
to  regard  dioxyacetone,  isomeric  to  lactic  acid,    CO        ,  as 

CH2.OH 
an  intermediate  product  of  alcoholic  fermentation,  because 
they  found  that  this  substance  uniformly  undergoes  fer- 
mentation, not  only  from  living  yeast  cells  but  from  ex- 
pressed juice  of  yeast  as  well,  if  juice  extracted  by  boiling 
( containing  the  ' '  coenzyme  " )  be  added.     Eecently  A.  Slator 

47 H.  Euler  (Stockholm),  Zeitschr.  f.  physiol.  Chem.,  11,  311,  1911. 
48  A.  Slator,  Ber.  d.  deutsch,  ehem.  Gesellsch.,  J,0,  123,  1907. 
**  E.  Büchner  and  J.  Meisenheimer,  Ber.  d.  deutsch,  chem.  Ges.,  J^S,  1773, 
1910. 


BUTYRIC  ACID  FERMENTATION  347 

has  rejected,  it  is  true,  the  view  that  dioxy acetone  is  an 
intermediate  product  of  alcoholic  fermentation,  from  the 
fact  that  while,  for  example,  a  decigram  of  dextrose  in  an 
experiment  was  completely  fermented  by  yeast  in  twenty 
minutes,  a  decigram  of  dioxyacetone  in  parallel  experiment 
underwent  practically  no  change.50  The  justice  of  such 
criticism  is,  however,  not  accepted  by  the  first-named  in- 
vestigators.51 

Recent  studies  of  Lebedew,  Harden  and  Young,  and  of 
Euler  seem  to  indicate  that  the  phosphoric  acid  contained  in 
the  fermentation  mixtures  plays  an  important  role  in  the 
fermentation,  uniting  with  hexose  to  form  an  ester  which 
much  more  readily  lends  itself  to  fermentation  cleavage; 
perhaps,  too,  the  possibility  of  an  intermediate  formation 
of  a  triose  or  triose-ester  in  the  course  of  the  fermentation 
ought  to  be  thought  of.52  At  best  the  whole  matter  is  at 
present  vague  and  uncertain. 

Butyric  Acid  Fermentation. — In  the  author's  opinion 
there  may  be  some  interest  in  the  observations  which  have 
been  made  upon  the  mechanism  of  butyric  acid  fermentation 
in  their  bearing  upon  the  study  of  the  processes  of  physio- 
logical catabolism  of  sugar.  Butyric  acid  may  be  formed 
from  hexoses  as  well  as  from  lactic  acid  from  fermentation. 
Büchner  and  Meisenheimer 53  conceive  of  the  process  in  this 
fashion :  that  the  sugar  first  is  split  into  lactic  acid,  and  this 
in  turn  into  acetaldehyde 54  and  formic  acid,  two  molecules 

50  A.  Slator,  Ber.  d.  deutsch,  ehem.  Ges.,  45,  43,  1912. 

51 E.  Buchner  and  Meisenheimer,  Ber.  d.  deutsch,  ehem.  Ges.,  45,  1632, 
1912;  cf.  also  Harden  and  Young,  ibid.,  40,  458,  1912;  Chick  (Lister  Instit., 
London),  Biochem.  Zeitschr.,  40,  479,  1912. 

62 A.  v.  Lebedew  (Instit.  Pasteur),  Ber.  d.  deutsch,  ehem.  Ges.,  44>  2932, 
1911;  Biochem.  Zeitschr.,  36,  248,  1911;  Ann.  Instit.  Pasteur,  25,  847,  1911; 
H.  Euler  (Stockholm),  with  Kullberg,  OhlsSn,  Fodor,  Zeitschr.  f.  physiol. 
Chem.,  14,  15,  1911;    76,  468,  1911;    Biochem.  Zeitschr.,  86,  401,  1911. 

83  E.  Büchner  and  J.  Meisenheimer,  Ber.  d.  deutsch,  chem.  Ges.,  41>  1910, 
1908. 

54 Cf.  statements  of  Kostytschew  (St.  Petersburg),  Zeitschr.  f.  physiol. 
Chem.,  19,  130,  1912,  upon  the  formation  of  acetaldehyde  in  alcoholic  fermenta- 
tion of  sugar. 


348         SUGAR  DESTRUCTION  IN  THE  ECONOMY 

of  the  aldehyde  then  condensing  into  aldol  and  this  finally 
becoming  converted  into  its  isomer,  butyric  acid : 

ALDOL  BUTYRIC   ACID 

-Formic  Acid  CH3  CH3 

^  I  I 

lactic  acid  — >■  Acetaldehyde    — >    CH.OH  CH2 

SUGAR     >  I  =  I 

lactic  acid  — >  Acetaldehyde    — >    CH2  CH2 

^Formic  Acid  COH  COOH. 

The    equation  for    butyric    acid  fermentation    is    usually 
written:  C6H1206  =  C4H802  +  2C02  +  2H2. 

Citric  Acid  Fermentation. — In  conclusion,  observations 
upon  citric  acid  fermentation  seem  to  be  not  without  some 
interest  in  connection  with  the  question  of  sugar  catabolism 
in  the  body,  particularly  because  citric  acid  is  present  in  the 
animal  body  as  a  constituent  of  milk.  In  culture  of  certain 
forms  of  citromycetes  on  appropriate  media  which  are  poor 
in  nitrogen  and  contain  an  addiment  of  carbonate  of  lime 
to  fix  the  citric  acid  as  the  relatively  insoluble  citrate  of 
calcium  and  thus  prevent  its  further  decomposition,  the 
fermentation  of  the  sugar  may  be  governed  so  that  actually 
only  citric  acid  and  carbonic  acid,  but  neither  alcohol,  acetic, 
lactic  or  succinic  acid,  will  appear.55  Obviously  the  branched 
chain  of  citric  acid  can  be  explained  only  on  the  supposition 
of  a  synthesis.  It  is  thought  that  it  can  be  explained,  for 
example,  by  the  combination  of  three  molecules  of  glycolic 
CH2.OH 

^OOH 

citric  acid 

!ÖH.;CH2.COOH  CH2COOH 

'' [H[ 

OH.C— COOH  — — >        OH.C.COOH 

JH'j 

"j"  CH2.COOH- 

iÖHJCH2.COOH 

But  it  must  be  said  that  there  is  as  little  proof  that  the 
synthesis  of  citric  acid  actually  takes  place  in  this  way,  as 

65  E.  Büchner  and  H.  Wüstenfeld,  Zeitschr.  f.  Biochem.,  11,  395,  1909. 


acid,  I  '  with  separation  of  water: 

CC~ 


CITRIC  ACID  FERMENTATION  349 

there  is  for  the  statement  that  the  hypothetical  intermediate 
product,  glycolic  acid,  actually  is  produced  from  sugar. 

All  in  all  there  is  no  wonder  that  the  real  nature  of  sugar 
catabolism  has  remained  a  secret  thus  far,  locked  in  the 
depths  of  the  economy,  when  we  have  never  been  able  to 
satisfactorily  explain  processes  like  alcoholic  fermentation 
and  the  various  types  of  acid  fermentation,  which  have  been 
known  so  long,  which  are  completed  in  the  greatest  quanti- 
ties in  vitro,  and  which  are  so  favorable  to  objective  study. 


CHAPTER  XV 

DIGESTION  AND  RESORPTION  OF  FATS 

Heeewith  we  turn  our  steps  to  a  new  field,  that  of  the 
biochemistry  of  fats.  It  will  undoubtedly  be  found  best  to 
continue  very  much  in  the  same  way  as  in  the  discussion  of 
protein  and  carbohydrate  metabolism,  beginning  with  the 
introduction  of  the  fats  into  the  digestive  tract,  then  dealing 
with  their  digestion  and  resorption,  thereafter  following 
them  on  their  way  through  the  chyle-  and  lymph-paths  and 
through  the  tissues,  up  to  where  they  and  their  cleavage 
products  begin  to  sink  into  the  depths  of  the  intermediate 
metabolism  and  pass  out  of  sight. 

The  Lipase  of  the  Stomach. — Beginning  then  with  consid- 
eration of  the  process  of  fat  digestion,  the  first  phase  to  be 
considered  is  the  gastric  digestion  of  fats.1  It  is  true  there 
has  been  much  written  upon  this  subject,  but  really  there  is 
very  little  that  can  be  said  about  it.  Doubtless,  according  to 
the  investigations  of  Volhard  and  others,  the  stomach  con- 
tains a  lipolytic  ferment  and  physiologically  the  splitting  of 
fat  begins  at  this  point.  Thus  London 2  found  in  a  dog  with 
gastric  fistula  that  about  one-third  of  the  fat  introduced  in 
emulsified  form  was  split  in  the  stomach  into  glycerol  and 
fatty  acids.  There  is  probably  no  doubt,  too,  that  at  times 
some  fat  is  resorbed  in  the  stomach.  Otto  Weiss  3  observed 
a  resorption  process  of  this  sort  in  the  stomach  of  ringed 
snakes  and  in  the  stomachs  of  newborn  dogs  and  cats;  in 
adult  human  beings,  however,  it  is  unquestionably  insigni- 
ficant.   Apparently,  too,  the  lipolytic  power  of  pure  gastric 


literature  upon  Gastric  Lipase:    C.  Oppenheimer,  Die  Fermente,  3d  ed., 
11,  pp.  15-16,  1909. 

2  E.  S.  London  and  M.  A.  Wersilowa,  Zeitschr.  f.  physiol.  Chem.,  56,  545, 

1908. 

30.  Weiss  (Physiol.  Instit.,  Königsberg)  ,  Pflüger's  Arch.,  lJf/f,  540,  1912; 
cf.  also  W.  Lamb.  Jour,  of  Physiol.,  J,0,  Proc.  Physiol.  Soc,  xxiii,  1910   (Fat 
Resorption  in  the  Stomach  of  Kittens). 
350 


PROBLEMS  OF  FAT  RESORPTION  351 

juice  is  distinctly  less  than  we  were  formerly  disposed  to 
believe.4  From  the  previously  mentioned  investigation  of 
Pawlow  and  Boldyreff  we  have  learned  that  immediately 
after  taking  fatty  food  it  is  very  easy  to  have  a  reflux  of  the 
duodenal  contents  into  the  stomach.  The  first  portion  of  fat 
on  entering  the  duodenum  may  in  the  same  manner  as  acid 
give  rise  to  a  pyloric  reflex ;  although  this  does  not  (as  in  case 
of  acid  stimulation)  lead  to  closure  of  the  pylorus,  but  to  an 
inhibition  of  the  normal  antral  peristalsis.  In  this  manner 
the  pancreatic  steapsin  may  gain  entrance  into  the  stomach 
and  take  part  here  in  the  cleavage  of  fats.5  A  number  of 
authors  used  to  be  disposed  to  deny  for  the  pure  gastric 
juice  any  active  lipolytic  function.  This  apparently,  how- 
ever, is  not  the  case ;  fat  cleavage  in  the  stomach  being  due 
in  part,  at  least,  to  the  influence  of  an  enzyme  secreted  by  the 
gastric  mucous  membrane,6  the  secretion  of  which  goes  on 
about  parallel  with  that  of  the  pepsin.7  Then,  too,  the  state- 
ment of  Laqueur  that  the  gastric  lipase  is  not  activated  by 
bile  does  not  bespeak  an  identity  with  the  pancreatic  steap- 
sin.8 Nevertheless,  no  particular  physiological  importance 
is  to  be  attached  to  the  lipolytic  processes  in  the  stomach  in 
the  author's  opinion. 

PROBLEMS  OF  FAT  RESORPTION 
Of  very  different  significance  is  the  question  as  to  the 
manner  in  which  fat  resorption  takes  place  in  the  intestine. 
It  is  well  known  that,  after  the  fat  has  become  mixed  in  the 
small  intestine  with  the  bile  and  pancreatic  secretion,  the 
greater  portion  of  it  is  changed  into  a  fine  emulsion.  For 
thirty  years  there  has  been  an  open  question  whether  the 

*E.  S.  London,  Zeitschr.  f.  physiol.  Chem.,  50,  125,  1906. 

6Cf.  S.  J.  Levites.  (St.  Petersburg),  Biochem.  Zeitschr.,  20,  220,  1909; 
Zeitschr.  f.  physiol.  Chem.,  49,  273,  1906. 

6Cf.  S.  v.  Pesthy  (F.  Tangl's  Lab.,  Budapesth),  Biochem.  Zeitschr., 
84,  147,  1911. 

7  Heinsheimer,  Deutsch,  med.  Wochenschr.,  1906,  1194. 

8E.  Laqueur  (P.  Gottlieb's  Lab.,  Heidelberg),  Hofmeister's  Beitr.,  8,  281, 
1906. 


352  DIGESTION  AND  RESORPTION  OF  FATS 

emulsified  fat  is  taken  up  as  such  by  the  intestinal  epi- 
thelium, or  whether  the  fat  is  first  broken  up  in  the  intestine 
into  glycerol  and  fatty  acids  and  these  components  absorbed 
in  a  dissolved  state,  to  reunite  into  neutral  fat  after  the 
absorption  is  accomplished. 

The  writer  would  prefer  not  to  enter  into  the  detailed 
phases  of  this  conflict  of  opinion  here.9  It  will  perhaps  be 
sufficient  to  state  categorically  that  the  view  maintained  by 
W.  Kühne,  J.  Muni?:,  M.  Nencki,  E.  Pflüger,  0.  Frank  and 
many  others,  that  a  process  of  solution  must  precede  the 
resorption  of  the  fat  (at  least  of  the  bulk),  has  been  upheld 
time  and  again.  "That  the  great  part  of  the  fat  is  split 
before  being  absorbed  and  thereby  changed  into  a  water- 
soluble  form,"  0.  Cohnheim 10  believes,  "is  certain,  and 
there  is  no  single  ground  and  not  a  single  observation  to 
prove  that  this  is  not  also  true  of  all  the  fat,  even  though 
the  negative  proof  that  no  known  portion  of  the  fat  passes 
the  epithelium  in  emulsied  form  has  not  yet  been  established 
and  in  fact  would  be  difficult  of  establishment  except  by  con- 
siderations of  a  general  nature." 

Probably  it  would  be  well  to  indicate  the  most  important 
reasons  which  support  this  view. 

Fat  Cleavage  and  Solution  of  the  Products  of  Cleavage. — 
It  should  be  clearly  understood  that  the  fat  in  the  intestine, 
in  by  far  its  greatest  proportion,  is  present,  not  as  neutral 
fat,  but  in  state  of  cleavage,  so  that,  especially  in  the  lower 
portions  of  the  intestine,  the  neutral  fat  occurs  in  far  smaller 
amounts  than  the  soaps  and  the  free  fatty  acids. 

Moreover,  one  should  keep  in  mind  the  important  fact 
(known  today,  but  not  known  in  the  early  days)  that,  be- 
cause of  the  presence  of  salts  of  the  biliary  acids,  of  lecithin, 

0  Literature  upon  Cleavage,  Besorption  and  Synthesis  of  Fat  in  the  Intes- 
tine: J.  Munk,  Ergebn.  d.  Physiol.,  1,  317-323,  1912;  O.  Cohnheim,  Nagel's 
Handb.  d.  Physiol.,  2,  555,  618-621,  1907;  Physiol,  d.  Verd.  u.  Ernähr.,  165- 
169,  1908;   E.  H.  Starling,  Handb.  d.  Biochem.,  3",  226-233,  1909. 

10  0.  Cohnheim,  Biochem.  Centralbl.,  1,  174,  1903. 


FAT  IN  THE  INTESTINAL  WALL  353 

and  of  Cholesterine  from  the  bile,  physical-chemical  condi- 
tions in  the  contents  of  the  small  intestine  are  determined  in 
which  the  cleavage  products  of  the  fat  are  kept  in  solution 
no  matter  whether  an  acid  or  an  alkaline  reaction  may 
prevail.  This  is  true  not  only  of  the  free  fatty  acids,  but 
also  of  their  relatively  insoluble  calcium  and  magnesium 
salts. 

Synthesis  of  Fat  in  the  Intestinal  Wall. — The  possibility 
of  fat  synthesis  in  the  wall  of  the  bowel  is  very  clearly  indi- 
cated from  the  experiments  of  J.  Munk,  and  those  of  0. 
Frank;  it  has  been  shown  that  in  the  chyle  of  the  thoracic 
duct  neutral  fat  is  present,  not  only  after  the  administration 
of  neutral  fat,  but  also  when  the  fatty  acids,  their  alkaline 
salts  and  esters  are  ingested.  Where  the  glycerol  comes  from 
which  is  necessary  in  such  a  synthetic  formation  is  not 
known;  it  must  suffice  for  the  present  to  know  that  it  can 
be  produced  apparently  in  unlimited  amount  by  the  intes- 
tinal wall.  If  this  were  not  true  it  would  be  impossible  to 
understand  how,  after  the  ingestion  of  large  quantities  of 
soaps  or  free  fatty  acids,  we  invariably  find  only  the  tri- 
glycerides in  the  lymph  of  the  thoracic  duct.  The  'discovery 
that  soaps  are  poisonous  when  introduced  directly  into  the 
circulation  and  that  for  this  reason  it  would  be  injudicious 
to  have  them  enter  the  circulation  unchanged,  is,  of  course, 
no  explanation.  We  are  here  brought  face  to  face  with 
another  unsolved  puzzle.  If,  however,  the  wall  of  the  bowel 
manages  to  carry  out  the  synthetic  formation  of  fat  from 
fatty  acids  and  glycerol  even  when  no  glycerol  is  provided 
for  it,  why  should  there  be  any  doubt  of  its  ability  to  com- 
plete the  synthesis  if  coincidently  with  the  fatty  acids 
equivalent  amounts  of  glycerol  are  resorbed  from  the  lumen 
of  the  bowel? 

From  recent  experiments  of  0.  Frank  "  it  appears  that 
ingested  monoglycerides  do  not  enter  the  chyle  as  such  but 

"A.  Argyris  and  0.  Frank  (Munich),  Zeitsch.  f.  Biol.,  59,  143,  1912. 
23 


354  DIGESTION  AND  RESORPTION  OF  FATS 

are  changed  into  triglycerides.  The  fatty  acids  essential 
for  this  synthesis  requisite  to  completely  transform  the 
monoglyceride  into  triglyceride  must  first,  however,  be  ob- 
tained from  cleavage  of  the  former.  The  inference  that  any 
extensive  cleavage  of  ingested  fat  must  occur  is  not  to  be 
made,  however,  from  this  point. 

Behavior  of  Non-saponifiable  Emulsions. — The  clearest 
indication  that  the  intestine  does  not  take  up  the  fat  ex- 
clusively in  the  form  of  an  emulsion,  but  at  least  partly  in 
a  dissolved  state,  may  be  seen,  to  the  author's  mind,  in 
the  fact  that  even  the  finest  emulsion  of  lanolin,12  petroleum 
or  paraffin  (material  which  from  its  chemical  peculiarities 
cannot  be  converted  into  a  dissolved  form  in  the  intestine) 
is  not  open  to  absorption.  If  neutral  fat  be  incorporated 
with  soft  paraffin  by  melting  them  together  and  the  mixture 
introduced  into  the  intestine  in  finely  emulsified  form,  the 
bowel  wall  takes  up  only  the  fat,  but  rejects  the  paraflfin.13 
The  writer  is  disposed  to  regard  this  as  a  thoroughly 
crucial  experiment.  The  statement  of  Hofbauer  and  S. 
Exner,14  subsequently  confirmed  by  Lafayette  Mendel, 
that  fat  colored  with  suitable  staining  reagents  can  pass 
into  the  chyle  ducts  as  stained  fat  has  no  further  reference 
to  the  method  of  resorption  in  the  opinion  of  Pflüger,  and, 
too,  of  L.  B.  Mendel,  than  to  indicate  that  these  staining 
substances  are  soluble  in  free  fatty  acids  or  in  a  biliary 
solution  of  fatty  acids  and  soaps,  the  latter  being  quite 
capable  of  acting  as  a  vehicle  to  aid  the  passage  of  the  stain- 
ing substances  through  the  wall  of  the  intestine  into  the 
chyle  ducts.15 

12  W.  Connstein,  Arch.  f.  Anat.  u.  Physiol.,  1899,  30;  A.  v.  Fekete  (Physiol. 
Instit.,  Budapesth),  Pflüger's  Arch.,  139,  211,  1911. 

13  V.  Henriques  and  C.  Hansen,  Centralbl.  f.  Physiol.,  Ik,  313,  1900. 

"L.  Hofbauer  (S.  Exner's  Lab.,  Vienna),  Pflüger's  Arch.,  81,  263,  1900; 
8k,  619,  1901;  Zeitschr.  f.  klin.  Med.,  kl,  475,  1902;  S.  Exner,  Pflüger's  Arch., 
84,  628,  1901 ;   L.  B.  Mendel  (Yale  Univ.) ,  Amer.  Jour,  of  Physiol.,  24,  493,  1909. 

"E.  Pflüger,  Pflüger's  Arch.,  81,  375,  1900;  85,  1,  1901;  L.  B.  Mendel, 
1.  c;  cf.  also  L.  B.  Mendel  and  A.  L.  Daniels  (Yale  Univ.),  Jour,  of  Biol. 
Chem.,  13,  71,  1912. 


OBSERVATIONS  UPON  FAT  RESORPTION  355 

Finally,  as  0.  Cohnheim  believes,  the  very  existence  in 
the  intestine  of  fat  splitting  ferments  seemingly  would  be 
inexplicable  and  superfluous,  if  it  were  true  that  the  resorp- 
tion is  exclusively  that  of  fat  in  emulsion. 

Histological  Observations  Bearing  Upon  Fat  Resorption. 
— To  Pfluger's  objections,  however,  Sigmund  Exner16  sug- 
gests that  histological  examination  always  has  made  it  look 
as  though  a  part  of  the  fat  is  resorbed  without  being  split. 
"I  have  always  regarded  it  as  probable,"  says  Exner,  "that 
fat  is  absorbed  in  part  unsaponified,  having  followed  since 
the  sixties  a  number  of  investigations  conducted  in  the 
Vienna  Physiological  Institute  bearing  upon  the  path  of 
resorption,17  and  having  invariably  found  features  which 
upheld  this  idea.  ...  As  the  hypothesis  that  all  fat  is 
changed  into  a  soluble  form  before  absorption  and  is  re- 
formed after  absorption  gained  more  and  more  adherence  I 
was  forced  to  say  to  myself :  If  in  the  first  place  we  see  the 
fat  droplets  (possibly,  too,  droplets  of  fatty  acids)  in  the 
contents  of  the  intestine,  in  the  rodded  border  of  the  cells, 
in  the  protoplasm  of  the  epithelial  cells,  and  finally  in  the 
chyle  vessels,  is  it  not  more  likely  that  all  these  droplets  are 
of  essentially  identical  origin  and  that  we  are  catching  them 
first  before  absorption  and  then  step  by  step  in  their 
progress,  than  that  the  droplets  which  we  find  within  the 
intestinal  lumen  are  as  yet  to  undergo  solution,  and  that 
those  right  alongside  of  them  in  the  rodded  cell  border  or 
in  the  cell  protoplasm  have  already  reseparated  from  such 
a  solution,  that  is  to  say,  have  been  regenerated?  .  .  . 
Solutions  go  through  all  forms  of  epithelium;  fat  in  any 
important  amount  especially  through  that  of  the  small  in- 
testine; is  it  purely  a  matter  of  chance  that  no  other 
epithelium  but  that  lining  the  small  intestine  is  provided 
with  that  peculiar  border  which  in  its  construction  from 
parallel   rods   arranged  in  palisade  manner  cannot  help 

16  S.  Exner,  Pfluger's  Arch.,  8-$,  628,  1901. 

17  E.  Brücke,  S.  v.  Basch,  F.  v.  Winiwarter. 


356  DIGESTION  AND  RESORPTION  OF  FATS 

suggesting  a  sieve-like  purpose?  ...  I  am  well  aware 
that  this  is  all  based  on  probabilities,  and  would  not  care  to 
bring  it  forward  if  there  were  clear  proof  evident  on  the 
other  side.  But  there,  too,  I  recognize  nothing  but  argu- 
ments based  upon  probability.  For  even  if  anyone  had 
proved  that  in  this  or  that  particular  instance  all  the  fat  had 
undergone  cleavage  or  saponification  before  being  absorbed, 
it  would  be  far  from  proving  that  invariably  this  is  the  case 
or  even  usually  true. ' ' 

Many  histological  studies  have  been  made  to  come  nearer 
the  solution  of  the  secrets  of  fat  resorption.  The  synthetic 
production  of  fat  from  soaps  and  glycerol  formerly  main- 
tained by  many  has  as  a  fact  not  been  confirmed  by  experi- 
ments upon  excised  living  intestinal  mucosa ; 18  studies  from 
Fano  's  laboratory  in  Florence 19  have,  on  the  contrary, 
shown  that  the  epithelial  cells  of  the  intestinal  mucosa  when 
brought  in  contact  with  oleic  acid  or  a  solution  of  sodium 
oleate  become  loaded  with  fatty  acid  which  can  be  demon- 
strated by  staining  with  osmic  acid ;  neutral  fat,  however, 
is  not  taken  up.  We  are  in  this  case  undoubtedly  dealing 
with  a  true  physical  solution  phenomenon,  one  not  mani- 
fested by  the  epithelium  of  the  oesophagus  and  stomach,  but 
which  can  be  demonstrated  with  intestinal  mucosa  even 
when  hardened  in  f  ormol,  and  which  is  probably  due  to  some 
solvent  which  the  cells  contain  for  oleic  acid. 

Formerly  a  great  deal  of  importance  was  ascribed  to 
tracing  the  fat  droplets  in  their  passage  through  the  epi- 
thelial cells  of  the  intestine.  For  example,  observations  like 
those  of  Cuenot  upon  the  intestine  of  Crustacea,  in  which  the 
fat  globules  are  apparent  only  in  the  portion  of  intestinal 
epithelium  exposed  to  the  lumen,  were  regarded  as  particu- 
larly valuable.  Since  we  have  come  to  realize  that  fats  may 
be  masked  in  the  presence  of  proteins  so  that  they  are  no 

18  O.  Frank  and  A.  Ritter  (Physiol.  Instit.,  Munich),  Zeitschr.  f.  Biol.,  47, 
251,  1906;    Moore,  Proc.  Roy.  S'oc,  72,  134,  1903. 
18  G.  Rossi,  Arch,  di  Fisiol.,  5,  381,  1908. 


RESORPTION  OF  SOAPS  357 

longer  demonstrable  by  means  of  osmic  acid,20  the  interest 
in  these  and  similar  observations  has  perceptibly 
diminished. 

According  to  the  studies  of  Noll  and  those  of  many  of 
the  older  observers,  a  portion  of  the  fat  taken  up  by  the 
intestinal  epithelium  leaves  the  latter  immediately ;  another 
portion  first  runs  together  into  larger  droplets,  these  then 
gradually  passing  out  into  the  chyle  vessels.21  Step  by  step 
the  process  first  shows  the  fat  granules  in  the  lymph  clefts 
of  the  villus ;  passing  thence  with  the  lymph  which  transudes 
from  the  capillaries  into  the  central  chyle  vessel,  and  finally 
along  the  mesenteric  lymph  passages  into  the  thoracic  duct, 
the  contraction  of  the  musculature  of  the  villi  acting  as  the 
propelling  force.  When  fat  resorption  is  in  active  process 
the  exposed  intestine  shows  the  chyle  passages  filled  with 
milky  fluid. 

Resorption  of  Soaps. — As  to  the  further  question  in  what 
form  the  fat  is  most  readily  resorbed,  it  was  formerly  the 
tendency  to  assume  that  soap  solutions  introduced  into  an 
intestinal  loop  are  particularly  suited  for  resorption.  How- 
ever, experiments  made  in  the  Zuntz  Institute22  have  shown 
that  in  dogs  with  Thiry-Vella  fistulas  of  the  upper  portions 
of  the  intestine  where  a  prompt  resorption  of  fat  emulsions 
takes  place,  soap  solutions  are  not  resorbed  even  after  bile 
and  pancreatic  juice  are  added.  (On  the  other  hand,  in 
case  of  fistulas  of  the  lower  parts  of  the  bowel  soaps  were 
readily  absorbed.)  The  author,  in  collaboration  with 
J.  Schütz23  and  with  Bleibtreu,24  has  also  noted  a  poor 
resorption  of  soap  solutions  from  isolated  intestinal  loops. 

20  G.  Rossi,  Arch,  di  Fisiol.,  4,  429,  1909. 

21  A.  Noll  (Physiol.  Instit.  Jena),  Arch.  f.  Anat.  u.  Physiol.,  1907,  349; 
Physioiogentag  Würzburg,  1909 ;  Centralbl.  f .  Physiol.,  23,  290,  1909 ;  Pflüger's 
Arch.,  136,  208,  1910;  cf.  also  Literature:  E.  H.  Starling,  Handb.  d.  Biochem.. 
3",  226-228,  1909. 

--W.  Croner  (Lab.  of  N.  Zuntz,  Berlin),  Biochem.  Zeitschr.,  23,  97,  1909. 
23  O.  v.  Fürth  and  J.  Schütz,  Hofmeister's  Beitr.,  10,  462,  1907. 
81  M.  Bleibtreu,  Deutsch,  med.  Wochenschr.,  1906,   1233. 


358  DIGESTION  AND  RESORPTION  OF  FATS 

One  might  be  disposed,  perhaps,  to  use  this  as  an  argument 
against  the  above  stated  theory  of  hydrolytic  fat  cleavage 
in  the  intestine.  But  from  the  present  status  of  the  general 
question  the  author  would  prefer  to  interpret  these  observa- 
tions as  indicating  that  it  makes  a  distinct  difference  whether 
the  neutral  fat  is  hydrolyzed  little  by  little  and  immediately 
elaborated,  or  whether  the  intestine  is  flooded  beyond 
physiological  possibilities  by  large  and  presumably  not  in- 
different quantities  of  soaps. 

For  the  rest,  mixtures  of  fatty  acids  are  apparently  at 
times  absorbed  with  more  difficulty  than  their  correspond- 
ing sodium  salts.25 

The  rapidity  of  resorption  of  neutral  fats  depends  in 
large  measure  upon  the  melting  point  of  the  fat  concerned, 
the  fats  with  high  melting  points  (as  tallows)  being  taken 
up  more  slowly  and  less  fully,  than  oily  and  lard-like  fats, 
this  explaining  to  some  degree  why  the  fats  passed  with 
fecal  matter  show  a  higher  melting  point  than  the  corre- 
sponding fats  in  the  food.26 

Method  of  Study  With  Isolated  Intestinal  Loops. — Be- 
fore proceeding  further,  some  reference  should  be  introduced 
here  upon  the  methods  applicable  in  experiments  upon  fat 
absorption.  Some  years  ago  we  were  accustomed  to  regard 
the  method  of  the  "isolated  intestinal  loops"  very  highly 
in  all  sorts  of  absorption  experiments,  and  fancied  that  we 
were  working  under  precise  "physiological"  conditions 
when  employing  this  method.  When,  several  years  ago,  the 
author,  in  association  with  Julius  Schütz,27  undertook  to 
study  fat  resorption  from  isolated  loops  high  hopes  were 
centred  in  the  experiments,  particularly  because  the  tech- 
nic  employed  was  a  very  distinct  improvement  upon  that 

26  S.  Levites  (Instit.  of  Exper.  Med.,  St.  Petersburg),  Zeitschr.  f.  physiol. 
Chem.,  53,  349,  1907. 

28  J.  Munk,  F.  Müller,  Aruschnik,  Levites  (1.  c),  F.  Tangl  and  A.  Erd%i 
(Budapesth),  Biochem.  Zeitschr.,  34,  94,  1911. 

*  O.  von  Fürth  and  J.  Schütz,  1.  c. 


INFLUENCE  OF  PANCREATIC  JUICE  359 

of  their  predecessors.28  In  order  to  diminish,  as  far  as 
possible,  the  untoward  effects  of  chilling  which  is  unavoid- 
able in  intestinal  operations,  the  experimenters  made  use 
of  a  warm  operating  table  made  of  a  large  tin  box  provided 
with  a  heating  coil,  this  enclosing  the  whole  narcotized  ani- 
mal (cat) ;  the  exposed  intestine  was  spread  out  on  com- 
presses wet  with  warm  physiological  salt  solution,  kept 
moist  with  the  latter,  and  replaced  immediately  after 
application  of  the  ligatures  and  injection  of  the  fluid  under 
investigation,  with  the  usual  further  steps.  In  spite  of  all 
their  effort  and  care  the  resorptive  efficiency  of  an  intestinal 
loop  thus  prepared  was  so  low  in  comparison  with  the 
physiological  effectiveness  of  the  normal  intestine,  that  the 
writer  has  lost  all  confidence  in  studies  based  on  the  method 
of  tying  off  intestinal  loops,  and  can  only  regret  the  heca- 
tombs of  animals  which  the  method  has  cost  and,  in  spite  of 
this  warning,  is  likely  to  cost  in  the  future.  To-day,  now  that 
Pawlow  and  London  have  shown  us  how  we  can  arrange  our 
resorption  experiments  under  practically  physiological  con- 
ditions by  means  of  the  polyfistula  method,  this  pseudo- 
physiological  procedure  has  lost  all  justification  for  its 
continuance,  in  the  opinion  of  the  writer. 

INFLUENCE    OF   THE    PANCREATIC   JUICE    AND    THE    BILE 
UPON  FAT  DIGESTION 

We  come  now  to  the  presentation  of  the  important  ques- 
tion of  the  part  taken  by  the  biliary  and  pancreatic  secre- 
tions in  fat  digestion.  That  these  two  secretions  are  actu- 
ally concerned  in  the  process  was  proved  as  early  as  1852 
by  Bidder  and  Schmidt,  and  is  further  indicated  from  the 
observations  of  Claude  Bernard,  who  found  in  rabbits  (in 
which  the  pancreatic  duct  opens  some  distance  below  the 
common  biliary  duct  in  the  small  intestine)  that  after  a  diet 

28  H.  J.  Hamburger,  Arch.  f.  Anat.  u.  Physiol.,  1900,  433 ;  H.  von  Tappeiner, 
Zeitschr.  f.  Biol.,  45,  222,  1908;  T.  Hattori,  F.  Hercher  (Bleibtreu's  Lab.), 
Inaug.  Dissert.,  Greifswald,  1905,  1907. 


360  DIGESTION  AND  RESORPTION  OF  FATS 

rich  in  fat  the  lymph  vessels  begin  to  show  injection  with 
the  milk-white  chyle  from  that  level  of  the  bowel  where 
these  two  secretions  become  mixed  with  the  intestinal  con- 
tent. Dastre  made  a  very  similar  observation  in  the  dog,  in 
which  animal  he  ligated  the  bile  duct  and  opened  the  gall 
bladder  by  a  fistula  into  the  middle  of  the  small  intestine, 
below  which  point  mixture  of  the  chyme  first  took  place 
with  the  bile,  the  commingling  of  the  pancreatic  secre- 
tion occurring,  of  course,  normally.  A  long  series  of  obser- 
vations on  animals  and  man,  in  which  after  exclusion  of  one 
of  the  two  secretions  or  of  both  the  utilization  of  fat  was 
manifestly  reduced,  proved  the  fact  that  normal  digestion 
of  fat  presupposes  the  combined  effect  of  both  secretions.29 
According  to  the  clinical  observations  of  T.  Brugsch  acute 
or  chronic  degenerative  pathological  processes  in  the  pan- 
creas of  man  impair  the  fat  absorption  to  a  very  consider- 
able degree  (50-60  per  cent.) ;  but  if  in  addition  to  the 
disturbance  of  the  pancreatic  secretion  there  is  associated 
a  cessation  of  the  normal  biliary  flow  the  loss  of  fat  may 
amount  to  as  much  as  80  to  90  per  cent. — that  is  to  say,  the 
bulk  of  the  fat  leaves  the  intestine  unabsorbed.  It  may  be 
readily  understood  why  by  artificially  furnishing  bile  and 
pancreatic  juice  one  may  succeed  in  favorably  influencing 
disturbances  occasioned  by  the  loss  of  these  secretions.  So, 
too,  the  addition  of  bits  of  pancreas  to  the  food  may  appre- 
ciably improve  the  utilization  of  fat,  according  to  the  state- 
ments of  Sandmeyer.30 

28  C.  Voit,  1882;  F.  Röhmann,  1882;  F.  Müller,  1887;  J.  Munk,  1890; 
Minkowski  and  Abelmann,  1890;  A.  Dastre,  1891;  Sandmeyer,  1894;  Harley, 
1895;  Hedon  and  Ville,  1897;  Rosenberg,  1898;  Albu,  1900;  A.  Schmidt,  1905; 
F.  Umber  and  T.  Brugsch,  Arch.  f.  exper.  Pathol.,  55,  164,  1906;  T.  Brugsch 
(Umber's  Clinic),  Zeitschr.  f.  klin.  Med.,  58,  518,  1906.  Literature;  upon  the 
Importance  of  the  Bile  and  Pancreatic  Secretion  for  Fat  Digestion:  J.  Munk, 
Ergebn.  d.  Physiol.,  1,  323-325,  1902;  O.  Prym,  Handb.  d.  Biochem.,  3",  116- 
118,  1909;  E.  H.  Starling,  ibid.,  pp.  228-230;  A.  Magnus-Levy,  Handb.  d. 
Pathol,  d.  Stoffwechsels,  2d.,  1,  32-39,  1906. 

30  W.  Sandmeyer  (Physiol.  Instit.,  Marburg),  Zeitschr.  f.  Biol.,  81,  12,  1895; 
Inouye  and  T.  J.  Sato,  Arch.  f.  Verdauungskr.,  17,  185,  1911;  M.  Adler  (Sena- 
tor's Clinic),  Zeitschr.  f.  klin.  Med.,  66,  302,  1908. 


EXTIRPATION  OF  PANCREAS  361 

Influence  of  Extirpation  of  the  Pancreas  Upon  Fat  Re- 
sorption.— Taking  up  here  the  question  of  the  mode  of 
action  exercised  by  the  bile  and  pancreatic  secretion  on  fat 
resorption,  brief  reference  may  be  appropriately  made  first 
to  the  ideas  which  U.  Lombroso  has  evolved  as  to  the  in- 
fluence of  the  pancreas.  These  rest  upon  the  statement 
made  by  a  number  of  authorities,  that  it  is  by  no  means  the 
same  thing  for  proper  utilization  of  the  fat  whether  we 
merely  ligate  the  pancreatic  ducts  or  completely  extirpate 
the  whole  gland.  Thus  Rosenberg  after  the  first  procedure 
noted  no  striking  disturbance  of  fat  utilization  in  dogs ;  but 
as  soon  as  he  entirely  ablated  the  gland  (already  markedly 
degenerated  in  sequence  to  the  ligation),  marked  disturb- 
ance ensued.31  Observations  of  the  same  sort  were  repeat- 
edly made  by  U.  Lombroso,32  R.  Fleckseder 3S  and  P.  C.  P. 
Jansen.34  The  first  of  these  suggested  the  theory  (with 
reference  to  the  fact  that  after  total  extirpation  of  the 
pancreas  there  may  at  times  be  observed  fatty  degeneration, 
crowding  of  the  fat  depots  of  the  body  and  even  fat  secretion 
into  the  intestine)  that  the  pancreas  may  be  involved  in  in- 
terruption of  the  natural  process  of  fat  metabolism  not  only 
by  loss  of  the  mixture  of  its  external  secretion  with  the  intes- 
tinal contents,  but  also  by  an  internal  secretion  which  is 
given  off  into  the  circulating  blood  and  by  which  it  governs 
the  fat  transformation  in  the  same  way  that  it  regulates  the 
carbohydrate  metabolism.35  To  properly  interpret  this  idea 
one  should  keep  especially  in  mind  that  total  pancreatic  ex- 

81  S.  Rosenberg,  Pflüger's  Arch.,  10,  371,  1898. 

82  U.  Lombroso  (Turin),  Arch.  Ital.  de  Biol.,  Iß,  336,  1904;  Pflüger's  Arch., 
112,  531,  1906;  Arch.  f.  exper.  Pathol.,  56,  357,  1907;  60,  99,  1908;  Arch,  di 
Fisiol.,  8,  209,  1910. 

33  R.  Fleckseder  (H.  H.  Meyer's  Lab.,  Vienna),  Arch.  f.  exper.  Pathol.,  59, 
407,  1908. 

34  P.  C.  P.  Jansen  (Physiol.  Instit.,  Amsterdam) ,  Zeitschr.  f.  physiol.  Chem., 
12,  158,  1911. 

85 O.  Gross  (Steyrer's  Clinic,  Greifswald),  Deutsch.  Arch.  f.  klin.  Med., 
108,  106,  1912,  has  also  recently  accepted  with  Lombroso  that  the  steatorrhea 
met  in  pancreatic  affections  is  due  to  a  loss  of  the  internal  secretion  of  the 
pancreas. 


362  DIGESTION  AND  RESORPTION  OF  FATS 

tirpation  is  a  very  serious  interference  which,  results  in  an 
inexpressible  wasting  of  the  body.  It  might  be  asked  very 
properly  whether,  when  "everything  is  upset"  in  metabo- 
lism in  sequence,  it  really  is  a  matter  of  much  wonder 
that  the  fat  digestion  should  also  become  disordered. 
Minkowski  noted  in  dogs  with  only  a  remnant  of  pancreatic 
tissue  transplanted  under  the  skin  of  the  abdomen,  the 
secretion  of  which  escaped  externally,  that  the  resorption 
of  fat  was  not  materially  reduced  provided  the  dog  could 
lick  up  the  secretion ;  when  the  secretion,  however,  was  with- 
held, interference  with  resorption  at  once  manifested  itself.36 
Off-hand  there  does  not  seem  to  be  any  insistent  reason  for 
ascribing  to  the  internal  secretion  of  the  pancreas,  besides 
its  dominant  part  in  the  metabolism  of  sugar,  a  second 
analogous  cardinal  function  in  relation  to  the  metabolism  of 
fats.  Disturbances  of  the  latter  process,  after  complete 
pancreatic  extirpation,  can  be  fully  explained  in  the  first 
place  on  the  basis  of  the  failure  of  its  external  secretion,  and 
in  the  second  place  by  the  general  disturbance  of  the  economy 
which  severe  pancreatic  diabetes  brings  with  it. 

There  will  probably  be  noted  a  contradiction  in  the 
author's  first  statement  that  the  combined  influence  of  the 
pancreas  and  the  bile  is  essential  to  the  proper  procedure 
of  fat  digestion  and  the  subsequent  point  to  the  effect  that 
ligation  of  the  pancreatic  ducts  need  not  necessarily  give 
rise  to  any  very  important  disturbance  of  fat  resorption. 
This  is,  however,  probably  only  a  superficial  contradiction. 
If  under  normal  conditions  the  bile  and  the  pancreas  co- 
operate in  connection  with  the  resorption  of  fat  (which  is 
undoubtedly  the  case  from  the  decisive  observations  of 
Claude  Bernard  and  Dastre  upon  the  chyle),  this  does  not 
preclude  the  possibility  of  the  economy  taking  advantage  of 
vicarious  means  of  compensating  in  some  measure  for  the 
loss  of  pancreatic  secretion.    We  know,  for  instance,  that 

38  G.  Burkhardt  (Minkowski's  Clinic,  Greifswald),  Arch.  d.  exper.  Pathol., 
58,  252,  1908;    cf.  also  the  observations  of  Abelmann  and  others. 


ACTIVATION  OF  PANCREATIC  STEAPSIN  363 

fat  cleavage  in  the  digestive  tract  is  not  accomplished  ex- 
clusively by  the  pancreatic  steapsin,  but  that  in  addition 
lipases  of  the  gastric  juice,  of  the  intestinal  secretion  and 
of  the  vast  numbers  of  microorganisms  in  the  intestine  are 
also  concerned  in  the  process. 

Activation  of  the  Pancreatic  Steapsin  by  the  Salts  of  the 
Biliary  Acids. — In  further  effort  to  properly  appreciate  the 
manner  in  which  the  pancreatic  secretion  and  the  bile  influ- 
ence the  digestion  of  fat,  we  at  once  are  met  by  the  important 
fact  that  the  fat-splitting  ferment  of  the  pancreas  is  greatly 
augmented  in  its  effectiveness  by  the  bile. 

The  first  statements  bearing  upon  the  reinforcing  influ- 
ence of  the  bile  upon  the  pancreatic  steapsin  are  probably 
to  be  ascribed  to  M.  Nencki.  These  were  confirmed  later 
by  a  number  of  observers.37  The  general  fact  in  itself  thus 
seemed  settled;  but  until  recently  it  was  not  known  to 
which  of  the  components  of  the  bile  this  characteristic  and 
(for  the  physiological  action  of  the  bile)  undoubtedly 
important  property  was  to  be  referred.  Contrary  to  the 
statements  of  Hewlett,  who  believed  he  was  in  position  to 
ascribe  its  most  important  role  in  fat  cleavage  to  the  lecithin 
of  the  bile,  the  author,  in  collaboration  with  Julius  Schütz, 
was  able  to  show  that  the  effect  (at  least  for  the  most  part) 
is  due  to  the  salts  of  the  bile  acids  (glycocholic  and  tauro- 
cholic  acids).  Although  these  results  were  regarded  as  en- 
tirely conclusive,  it  was  unquestionably  a  matter  of  satisfac- 
tion that  R.  Magnus  38  determined  further  that  the  sodium 
salts  of  synthetically  formed  biliary  acids  are  also  capable 
of  acting  as  powerful  activating  agents.  "In  the  synthetic 
production  of  the  two  biliary  acids,"  says  Magnus,  "which 
was  done  by  starting  with  cholalic  acid  and  producing  suc- 
cessively the  ethylester,  the  hydrazid  and  the  azid  of  this 

"Dastre,  1891;  Knauthe,  1898;  G.  C.  Bruno,  1899;  Babkin,  1903; 
K.  Glässner,  1904;  A.  W.  Hewlett,  1906;  cf.  Literature:  0.  v.  Fürth  and 
J.  Schütz,  Hofmeister's  Beitr.,  9,  28,  1906. 

38  R.  Magnus,  Zeitschr.  f.  physiol.  Chem.,  48,  376,  1906;  cf.  also  E.  F. 
Teorrine  (Lab.  of  the  College  of  France),  Biochem.  Zeitschr.,  23,  440,  1910. 


364  DIGESTION  AND  RESORPTION  OF  FATS 

acid,  there  were  so  many  and  such  interfering  procedures 
(prolonged  boiling  with  acids  and  alkalies,  treatment  with 
hydrazine  hydrate,  sodium  nitrite,  etc.)  required  that  it 
seemed  quite  impossible  that  any  substance  active  in  small 
amounts  could  remain  intact  and  maintain  itself  in  practi- 
cally unchanged  quantity  through  all  these  processes. 
.  .  .  The  augmenting  influence  of  the  bile  upon  fat  cleav- 
age by  the  pancreatic  juice  depends  upon  its  containing 
biliary  salts  of  alkalies.  The  economy  in  this  respect  works 
with  precisely  the  same  means  as  the  technical  chemist,  who 
splits  fats  today  with  ferments  and  activates  the  latter  by 
small  quantities  of  manganese  sulphate." 

Question  of  the  Complex  Nature  of  the  Pancreatic 
Steapsin. — Here  arises  the  further  question  of  just  how  this 
powerful  effect  (for  the  fat  splitting  action  of  the  pancreatic 
steapsin  can  be  increased  more  than  tenfold  at  times  by  the 
addition  of  small  amounts  of  bile)  is  to  be  interpreted.  The 
author's  pupil,  Hedwig  Donath,  whom  he  induced  to  take  up 
this  question  seriously,  answers  it  by  supposing  that  we  are 
here  dealing  with  the  conversion  of  an  inactive  zymogen  or 
proferment  into  an  efficient  enzyme,  a  slow  transformation 
being  also  possible ' '  spontaneously, ' '  but  greatly  accelerated 
by  the  catalytic  action  of  the  bile  salts.  From  this  it  is 
apparently  easy  to  appreciate  why  steapsin  preparations 
may  spontaneously  undergo  changes  of  such  a  character  that 
add  to  their  direct  effectiveness  but  diminish  their  capacity 
for  activation  by  cholic  acid.  Activation  of  the  pancreatic 
ferment  by  cholates  results  in  increasing  the  ferment  activity 
only  within  certain  limits  in  proportion  to  the  quantity  of 
cholic  acid  employed ;  from  this  limit  forward  further  addi- 
tion of  cholic  acid  is  not  followed  by  any  increase  in 
efficiency.39  This  discovery  is  of  general  interest  from  the 
fact  that  in  many  ways  it  suggests  certain  analogies  which 

39  H.  Donath,  Hofmeister's  Beitr.,  10,  390,  1907,  conducted  under  direction 
of  0.  v.  Fürth;  cf.  also  0.  Rosenheim,  Jour,  of  Physiol.,  JfO,  Proc.  Physiol.  Soc, 
1910 — Separation  of  the  Pancreatic  Lipase  from  Its  Coenzyme. 


SYNTHETIC  PRODUCTION  OF  FAT  365 

ferments  present  with  toxines.  It  has  been  especially  sug- 
gested, too,  that  enzymes,  just  as  toxines,  are  perhaps  com- 
posed of  two  parts,  one  a  thermostable  "amboceptor"  and 
the  other  a  thermolabile  ' '  complement. ' '  Observations  like 
those  of  H.  Donath,  of  the  possibility  of  partially  reactivat- 
ing pancreatic  steapsin  which  had  been  inactivated  by  ex- 
posure to  a  temperature  of  about  60°  C.  by  a  thermolabile 
agent  present  in  normal  horse  serum,  invariably  make  it 
seem  very  likely  that  the  pancreatic  steapsin  is  of  a  complex 
nature.  It  should  be  added,  too,  that  appearances  of  this 
and  similar  nature  fall  in  very  well  with  the  ideas  of  Victor 
Henri,  who,  on  the  basis  of  ultramicroscopic  observations, 
has  brought  into  the  reach  of  possibility  an  explanation  of 
' '  complement  effects ' '  from  purely  physical  factors.40 

Synthetic  Production  of  Fat  by  Reverse  Ferment  Action 
of  Lipase. — The  fermentative  kinetics  of  pancreatic  lipase 
has  been  closely  studied  from  a  number  of  standpoints  41 ;  but 
it  is  impossible  here  to  enter  into  the  details  of  this  phase  of 
the  subject,  which  belong  properly  to  the  sphere  of  physical 
chemistry.  Reference  may  be  made  merely  to  one  point, 
because  of  its  special  physiological  interest,  that  is,  the 
fact  that  the  lipases  concerned  in  digestion,  coming  from 
the  pancreatic  and  intestinal  secretions,  are  not  only 
capable  of  separating  fat  into  glycerol  and  fatty  acids,  but 
also  of  bringing  about  in  a  reverse  way  a  synthetic  produc- 
tion of  fat  from  its  components.  We  are  concerned  here 
with  a  true  reversible  enzyme  action, 

Gylcerol  +  Fatty  acids    <  >    Neutral  fat, 

which,  according  to  conditions,  can  take  place  in  either 
direction,  and  which  brings  somewhat  closer  to  our  under- 

40  V.  Henri,  Congress  of  Physiologists,  Heidelberg,  Aug.,  1907,  Cenfralbl. 
f.  Physiol.,  21,  477,  1907. 

41  Kastle  and  Löwenhart,  H.  Engel,  J.  Lewkowitseh  and  J.  J.  K..  Macleod, 
Taylor,  A.  Kanitz,  Zeitschr.  f.  physiol.  Chem.,  46,  482,  1905;  E.  F.  Terroine, 
Biochem.  Zeitschr.,  28,  404,  1910,  and  others.  Cf.  therein  the  Literature.  Cf. 
also  O.  Rosenheim  and  collaborators,  Jour,  of  Physiol.,  40,  Proc.  Physiol.  Soc, 
1910. 


366  DIGESTION  AND  RESORPTION  OF  FATS 

standing  the  fact  that  fat  which  has  undergone  cleavage  in 
the  lumen  of  the  intestine  is  regenerated  synthetically  in  the 
wall  of  the  bowel.42  Just  as  fat  cleavage  is  activated  by  the 
salts  of  the  biliary  acids,  so,  too,  is  the  fermentative 
synthesis  of  fat.43 

Cleavage  of  Fat  in  the  Intestine  in  the  Absence  of  Pan- 
cretic  Secretion. — Since,  as  above  pointed  out,  the  absorption 
of  fat,  at  least  for  the  greater  part,  can  be  completed  only 
after  complete  cleavage  according  to  the  more  recent  views, 
and  the  latter  is  very  much  augmented  by  the  influence  of  the 
bile,  disturbance  of  fat  resorption  might  at  first  glance  seem 
to  be  thoroughly  explained  after  loss  of  the  bile  and  pancre- 
atic secretion.  On  closer  consideration,  however,  this  ex- 
planation is  seemingly  subverted  by  the  fact  that  even  in  a 
case  of  this  sort  the  fat  which  appears  in  considerable  quanti- 
ties in  the  faeces  is  not  (as  might  have  been  expected)  an  in- 
tact neutral  fat,  but,  on  the  contrary,  seems  to  be  practically 
all  split  up  into  its  components.  This  has  confused  our  con- 
ceptions of  the  true  nature  of  fat  resorption  all  the  more,  be- 
cause, as  E.  H.  Starling 44  very  properly  remarks,  we  over- 
looked the  point  that  we  should  know  not  only  whether  the 
fat  has  been  split  in  the  digestive  tract  at  all,  but  whether 
the  cleavage  occurred  at  the  right  place,  that  is,  in  the  upper 
portion  of  the  intestine.  It  may  take  place  (probably  true 
in  case  of  diminutions  of  the  pancreatic  secretion)  through 
the  agency  of  microorganisms  only  in  the  lower  parts  of  the 
intestine,  where  it  is  apparently  too  late,  and  where  the 
intestine  is  unable  to  deal  with  the  products  of  cleavage. 

In  view  of  the  fact  that  resorption  of  fat  is  apparently 
much  more  seriously  interfered  with  when  the  flow  of  bile  is 
stopped  along  with  that  of  the  pancreatic  fluid,  than  when 

42  Hanriot,  J.  H.  Kastle  and  A.  S.  Löwenhart,  O.  Mohr,  H.  Pottevin,  Ann. 
Instit.  Pasteur,  22,  901,  1906;  H.  Donath,  1.  c;  A.  E.  Taylor,  Jour,  of  Biol. 
Chem.,  2,  87,  1906-1907;    W.  Dietz,  Zeitschr.  f.  physiol.  Chem.,  52,  279,  1907. 

43  A.  Hamsik  (Cech.  Univ.,  Prague),  Zeitschr.  f.  physiol.  Chem.,  59,  1,  1909; 
65,  232,  1910;    11,  238,  1911. 

44  E.  H.  Starling,  Handb.  d.  Biochem.,  S",  230,  1909. 


SOLVENT  POWER  OF  THE  BILE  367 

the  latter  alone  is  stopped,  it  is  important  to  call  attention  to 
the  point  that  the  bile  acts  as  an  important  activator  not  only 
upon  the  lipase  of  the  pancreatic  secretion  but  also  upon 
that  of  the  unmixed  intestinal  juice. 

Solvent  Power  of  the  Bile. — Since,  following  what  has 
been  said  above,  the  generally  acknowledged  powerful  effect 
of  the  bile  on  fat  digestion  does  not  seem  thoroughly  ex- 
plained by  its  influence  upon  fat  cleavage,  earnest  efforts  have 
been  made  to  discover  other  explanatory  possibilities.  One 
suggestion  has  brought  into  prominence  the  solvent  power 
of  the  bile  for  the  higher  fatty  acids,  and  lipoids  of  all  sorts. 
If,  for  example,  an  opaque,  milky  suspension  of  lecithin  be 
treated  with  a  solution  of  the  biliary  salts,  the  fluid  be- 
comes clear  at  once,  and  in  the  ultramicroscopic  field  the 
suspended  particles  may  be  watched  disappearing  from 
sight.45  The  combination  of  salts  of  the  biliary  acids, 
lecithin,  Cholesterine  and  mucin  in  the  bile  form  with  the 
soaps  a  physical-chemical  system  in  which  (as  we  have 
learned  from  the  studies  of  Moore  and  Rockwood,  Pflüger 
and  Rossi46)  fatty  acids  are  soluble  to  so  great  an  extent 
that,  as  a  matter  of  fact,  the  largest  amounts  which  could 
possibly  be  regarded  as  within  bound  of  physiological  oc- 
currence are  converted  to  a  water  soluble  form.  This  is  the 
more  important,  as  soaps  in  the  intestinal  contents  very 
readily  undergo  hydrolytic  dissociation  from  the  influence 
of  carbonic  acid,  fatty  acids  being  observable  as  a  conse- 
quence in  free  state  even  in  the  presence  of  notable  amounts 
of  sodium  carbonate.47  Whether,  in  addition  to  this  im- 
portant point,  the  favoring  influence  (at  one  time  looked 
upon  as  important)  of  the  alkali  contained  in  the  bile  upon 
emulsification  of  fat,  and  the  reduction  of  the  surface  ten- 
sion of  the  intestinal  contents  by  the  salts  of  the  biliary 

45  L.  Kalaboukoff  and  E.  F.  Terroine,  C.  R.  Soc.  de  Biol.,  66,  176,  1909. 

46  G.  Rossi  (G.  Fano's  Lab.,  Florence),  Arch,  di  Fisiol.,  4,  429,  1907,  cited 
in  Centralbl.  f.  Physiol.,  21,  811,  1907. 

47  G.  Rossi,  1.  c. 


368  DIGESTION  AND  RESORPTION  OF  FATS 

acids,48  or  whether  finally  an  increase  of  the  absorbing 
activity  of  the  intestinal  epithelial  cells  caused  by  the  bile, 
should  be  taken  into  consideration,  may  remain  where  they 
are. 

LIP^MIA 

Passing  a  step  further,  we  may  next  consider  the  route 
by  which  the  fat  passes  into  the  blood  stream,  and  the  form 
which  the  fat  taken  up  out  of  the  intestine  assumes  in  the 
blood. 

Resorption  Path  of  the  Fat. — That  a  part  of  the  fat  finds 
its  way  by  the  lymph  paths  and  thoracic  duct  may  be  seen  by 
direct  anatomical  study  of  an  animal  killed  after  a  meal  rich 
in  fatty  substances.  Many  observations,  as  those  of  Munk 
and  Eosenstein  on  a  girl  with  a  thoracic  duct  fistula,  indi- 
cate that  at  times  the  bulk  of  the  fat  follows  this  route. 
Without  question,  however,  a  portion  of  the  fat  goes  directly 
into  the  blood  stream.  J.  Munk  and  Friedenthal  observed 
after  ligating  the  thoracic  duct  and  feeding  freely  on  food 
rich  in  fat  (cream)  that  the  blood  sometimes  contained  up- 
wards of  six  times  the  normal  amount  of  fat,  so  that,  after 
preventing  coagulation  by  the  addition  of  ammonium  oxal- 
ate, the  blood  on  sedimentation  became  covered  with  a  thick 
layer  of  cream.49  In  the  writer 's  opinion  a  study  which  has 
attracted  but  little  notice,  made  in  Bottazzi's  laboratory  in 
Naples,50  should  be  regarded  as  of  special  importance  to 
the  question  of  the  route  of  fat  resorption.  From  animals 
during  fat  digestion  two  blood  specimens  are  taken  at  the 
same  time,  one  from  the  portal  vein  and  one  from  the  jugular 
vein;  and  these  are  compared  for  their  fat  content.  Did 
the  principal  stream  of  fat  pass  from  the  thoracic  duct  into 
the  jugular  vein  obviously  one  should  always  expect  that 
the  amount  of  fat  in  the  blood  of  the  latter  would  exceed 
that  of  the  portal  blood ;  actually,  however,  the  opposite  was 

48  Cf.  G.  Billard,  C.  R.  Soc.  de  Biol.,  61,  323,  1906. 

43  J.  Munk  and  H.  Friedenthal,  Centralbl.  f .  Physiol.,  15,  297,  1901. 

50  G.  d'Errico  (Bottazzi's  Lab.),  Arch,  di  Fisiol.,  k,  1908. 


H^EMOCONIOSIS  369 

found  to  be  the  case.  It  has  not  been  possible  to  recover 
from  the  lymph  of  the  thoracic  duct,  collected  during  the 
period  of  resorption  of  a  known  amount  of  fat,  more  than 
sixty  per  cent,  of  the  fat  which  disappeared  from  the  intes- 
tine. H.  J.  Hamburger 51  has  satisfied  himself  that  the  re- 
sorption of  soaps  from  loops  of  the  small  intestine  of  the 
dog  continues  even  after  the  recognizable  lymph  vessels  have 
been  ligated. 

Hatmoconiosis. — In  what  form  does  the  resorbed  fat  ap- 
pear in  the  blood?  After  free  fat  diet  the  plasma,  and,  too, 
the  serum  expressed  from  the  clotted  blood,  looks  milky; 
and  on  standing  a  cream-like  layer  may  be  formed  on  the 
surface  by  the  collection  of  the  fat  globules.  Kreidl  and 
Neumann  52  have  observed  in  ultramicroscopic  study  of  the 
blood  at  time  of  fat  resorption  the  appearance  in  the  dark 
field  of  great  numbers  of  shining,  very  minute  granules 
("haemoconiaB")  which  are  not  seen  in  the  blood  of  the  fast- 
ing human  being  or  of  one  on  fat-free  diet.  If  such  exami- 
nations of  the  blood  are  repeated  at  short  intervals  after  the 
ingestion  of  a  meal  rich  in  fat,  and  the  quantity  of  the 
particles  visible  in  the  field  be  estimated  each  time,  one  can 
recognize  a  gradual  accession  of  the  fatty  particles,  and 
after  a  maximum  has  been  reached  a  gradual  recession  suc- 
ceeding. About  twelve  hours  after  the  last  meal  the  serum 
of  healthy  human  beings  is  clear  and  free  from  haemoconiaa. 
In  cats  and  rabbits  the  highest  point  of  resorption  is  reached 
in  about  four  hours,  in  man  in  about  six  hours.53  These 
blood-dust  particles  seem  to  belong  exclusively  to  that  part 
of  the  fat  which  reached  the  blood  by  way  of  the  thoracic 
duct.  Solution  in  the  blood  cannot  be  said  to  take  place. 
The  particles  seem  to  disappear  from  the  blood  vessels 

51  H.  J.  Hamburger,  Arch.  f.  Anat.  u.  Physiol.,  1900,  554. 

82  A.  Neumann,  Centralbl.  f.  Physiol.,  21,  1907;  Wiener  klin.  Wochenschr., 
1.907;  A.  Kreidl  and  A.  Neumann,  Sitzungsber.  der  Wiener  Akad.  Mathem. 
Naturw.  Kl.,  120,  III,  February,  1911. 

63  A.  Kreidl  and  A.  Neumann,  1.  c;    E.  Neisser  and  H.  Bräuning  (Stettin), 
Zeitschr.  f.  exper.  Pathol.,  4,  747,  1907. 
24 


370  DIGESTION  AND  RESORPTION  OF  FATS 

by  traversing  the  capillary  wall  and  are  taken  up  in 
corpuscular  form,  as  are  other  suspended  particles  in  cer- 
tain cell  groups,  by  the  tissues,  especially  the  liver,  spleen 
and  bone-marrow.54 

Masking  of  the  Fat  in  the  Blood. — Information  obtained 
in  another  way  indicates,  however,  that  in  the  disappearance 
of  the  fat  from  the  blood  that  there  are  processes  of  a  very 
different  character  which  we  must  also  consider.  W.  Conn- 
stein  and  Michaelis  came  to  the  conclusion  that  there  exists 
a  lipolytic  function  of  the  blood.  If,  to  be  specific,  an 
emulsion  of  fat  be  mixed  with  blood  and  air  conducted 
through  it,  one  will  notice  an  appreciable  loss  in  the  ethereal 
extract.  That  an  ester-splitting  ferment  discovered  by 
Hanriot  in  the  blood  has  no  part  at  all  in  the  disappearance 
of  the  fat  from  the  blood  was  shown  by  careful  studies  long 
ago  by  Arthus,  and  also  by  Doyon  and  Morel.  The  latter 
authors  were  able  to  show  that  the  reduction  in  the  ethereal 
extract  obtained  from  blood  containing  fat  does  not  coincide 
in  the  least  with  cleavage  of  the  fat  into  fatty  acids  and 
glycerol.55 

Eecent  investigations,  among  which  those  of  Mansfeld,56 
of  Budapesth,  are  prominent,  have  shown  the  unexpected 
fact  that  in  this  puzzling  disappearance  of  the  fat  from  the 
blood  (aside  from  the  above  mentioned  escape  of  the  blood 
dust  particles  from  the  blood  vessels  through  the  walls  of 
the  capillaries  into  the  cells)  we  are  not  dealing  with  either 
a  cleavage  process  or  with  one  of  destruction,  but  rather 
with  a  process  of  masking.  It  was  mentioned  above  that  fat 
in  contact  with  albumin  (as  shown  in  Fano's  laboratory) 

54  S.  Biondi  and  A.  Neumann,  Wiener  klin.  Wochenschr.,  1910,  734; 
E.  Nobel  (S.  Exner's  Lab.,  Vienna),  Pfliiger's  Arch.,  134,  436,  1910;  J.  Leva 
(Berlin),  Berliner  klin.  Wochenscbr.,  1909,  961. 

55  Connstein  and  Michaelis,  Hamburger,  Weigert,  Arthus,  Doyon  and  Morel; 
cf.  the  Literature:  W.  Connstein,  Ergebn.  d.  Physiol.,  3',  210-223,  1904;  cf. 
also  the  statements  of  P.  Rona  and  L.  Michaelis,  Biochem.  Zeitschr.,  31,  345, 
1910,  as  to  the  existence  of  a  tributyrin-splitting  ferment  in  the  blood. 

68 G.  Manäfeld  (Pharmacol.  Instit.,  Budapesth),  Magyar  Orvosi  Arch.,  9, 
cited  in  Jahresber.  f.  Tierchem.,  1908,  84;  Pfliiger's  Arch.,  129,  46,  63,  1909. 


MASKING  OF  FAT  371 

may  escape  detection  by  osmic  acid  staining.  From  Mans- 
f eld's  studies  it  would  appear  that  the  resorbed  fat  enters 
in  part  into  some  sort  of  combination  with  the  protein  in 
the  blood,  and  thus  becomes  insoluble  in  ether.  We  are 
compelled,  therefore,  to  distinguish  in  the  blood  between 
the  free  fat  and  the  combined  fat.  Only  the  free  fat  can  be 
supposed  capable  of  passing  through  the  capillary  walls 
and  entering  the  tissues.  Possibly,  too,  changes  of  lipoids 
may  play  some  part  in  the  apparent  disappearance  of  fat  in 
the  blood.57 

Relation  of  the  Masking  of  Fat  to  Fatty  Degeneration. — 
That  crude  interferences  like  heat  coagulation,  the  influence 
of  alcohol  or  peptic  digestion  are  capable  of  breaking  the 
delicate  combinations  between  fat  and  protein  (at  first  sup- 
posed necessarily  to  be  physical  but  later  regarded  as  chem- 
ical in  character)  58  is  entirely  obvious.  Mansfeld  is,  how- 
ever, of  the  opinion  that  changes  of  a  more  intricate  type  are 
also  capable  of  destroying  this  union  and  that  fatty  degen- 
eration and  fat  metastasis  in  pathological  conditions  (as  in 
phosphorus-  and  acid-poisoning,  starvation,  etc.)  are  closely 
connected  with  the  process.  Since  infusion  of  dilute  lactic 
acid  under  proper  conditions  sets  free  the  fat  in  combina- 
tion with  protein  in  the  blood  and  enables  it  to  pass  out 
through  the  capillary  wall,  Mansfeld  regards  it  probable  that 
the  fatty  degeneration  of  phosphorus  poisoning  is  related 
with  the  accumulation  of  lactic  acid  in  the  blood.  Such  an 
assumption  would,  however,  seem  justified  only  after  proof 
by  careful  quantitative  experiments  that  the  amounts  of 
lactic  acid  which  appear  in  the  blood  in  phosphorus  poisoning 

51  L.  Berczeller  (F.  Tangl's  Lab.,  Budapesth),  Biochem.  Zeitschr.,  4Jh  193, 
1912. 

58  Boggs  and  Morris,  Jour,  of  Exper.  Med.,  11,  563,  1909,  who  have  observed 
a  distinct  lipamia  in  animals  after  repeated  bleeding,  found  that  the  milky 
serum  is  not  cleared  up  by  shaking  with  ether,  but  is  readily  cleared  after 
adding  ammonium  oxalate.  It  would  require  special  study  to  determine 
whether  the  removal  of  calcium  is  the  essenial  point  in  this  procedure  and 
whether  we  are  not  rather  dealing  with  some  kind  of  disturbance  of  the  physical- 
chemical  equilibrium. 


372  DIGESTION  AND  RESORPTION  OF  FATS 

are  capable  of  breaking  up  the  combinations  between  fat  and 
protein  in  the  blood,  although  subject  to  instant  neutraliza- 
tion by  the  blood  alkali.  As  long  as  we  lack  this  proof  the 
fact  that  in  phosphorus  poisoning  the  relation  between  free 
and  combined  fat  in  the  blood  is  altered  so  that  the  former 
predominates,  is  open  to  a  number  of  other  interpretations. 

Pathological  Lipcemias. — Coming  to  the  pathological 
lipsemias,59  quite  a  number  of  pathological  conditions  are 
known  in  which  an  abnormal  accumulation  of  fat  often 
occurs  in  the  blood.  This  is  true  especially  of  starvation, 
of  the  various  forms  of  anaemias  and  cachexias,  of  diabetes 
(both  the  severe  human  type  and  experimentally  produced 
pancreatic  and  phloridzin  diabetes),  of  chronic  alcoholism 
and  long  continued  narcoses,  of  phosphorus  poisoning  and 
a  number  of  other  toxic  conditions. 

It  is  scarcely  possible,  in  the  present  state  of  our  knowl- 
edge, to  consider  these  different  lipsemias  from  a  single 
standpoint.  But  one  may  at  least  endeavor  to  clear  up  a 
group  of  physiological  factors  which  are  open  to  consider- 
ation in  this  connection. 

Lipcemia  from  Mobilization  of  Fat  Deposits. — As  a  very 
important  element  in  many  of  these  lipaBmias  we  may  safely 
consider  a  compensatory  regulative  effort  on  the  part  of 
the  economy  enabling  it  to  mobilize  its  supply  of  fat  in  case 
of  need,  as  in  starvation.  The  importance  of  this  fat 
mobilization,  which  manifests  itself  anatomically  in  the  loss 
of  the  fat  accumulations  in  various  positions,  may  be  at  once 
appreciated,  if  we  recall  that  the  body  in  long-continued 
starvation,  as  soon  as  its  glycogen  has  been  used  up,  calls 
upon  fat  combustion  to  cover  at  least  nine-tenths  of  its  de- 
mand for  energy.  That  this  may  become  possible,  however, 
the  fat  must  lend  itself  to  ready  movement.  The  liver  is 
apparently  frequently  the  first  objective  point,  and  may 
in  many  pathological  states  be  found  the  seat  of  an  excess 
of  fat  (as,  typically,  in  dogs  with  pancreatic  diabetes).  Here 

68  Literature  on  Lipaemias :  A.  Magnus-Levy  and  L.  F.  Meyer,  Handb.  d. 
Biochem.,  h' ,  459-470,  1909. 


DIABETIC  LIPiEMIA  373 

there  may  be  manifested  a  certain  antagonism  between 
glycogen  and  fat,  the  site  left  vacant  by  the  disappearance 
of  the  glycogen  coming  to  be  occupied  by  the  fat  (not  so 
much  in  the  anatomical  sense  as  functionally,  in  the  view 
taken  by  G.  Eosenf eld) .  This  point  will  be  again  taken  up  in 
connection  with  fatty  degeneration.  The  classical  example 
of  this  type  of  fat  mobilization  is  seen  in  the  lipaemia  of  the 
Ehine  salmon  (during  their  migration  without  food)  ob- 
served by  Miescher.  In  starving  mammals  the  time  of  li- 
paemic  occurrence  perhaps  may  be  regarded  as  correspond- 
ing with  the  time  when  the  supply  of  carbohydrate  has 
become  completely  exhausted.60 

Diabetic  Lipaemia. — It  is  not  easy  to  see  why  a  mobiliza- 
tion of  fats  should  not  be  assumed  also  for  the  lipaemia  in 
phloridzin  diabetes,  in  that  due  to  removal  of  the  pancreas,61 
and  in  protracted  diabetic  coma.62  Diabetic  coma  seems  in 
the  vast  majority  of  cases  to  be  associated  with  lipaemia,  in 
which  the  amount  of  fat  in  the  blood  may  reach  an  enormous 
grade  of  twenty  per  cent,  or  more;  the  blood  assuming  an 
appearance  not  unlike  cream  and  chocolate,  and  on  ophthal- 
moscopic examination  the  retina  showing  directly  a  milky 
turbidity.  According  to  G.  Klemperer  in  such  cases  we  are 
really  dealing  with  a  lipoidaemia  rather  than  a  lipaemia,  the 
bulk  of  the  ethereal  extract  consisting,  not  of  fat,  but  of 
Cholesterine  and  lecithin.  For  this  reason  he  would  in- 
terpret diabetic  lipaemia  not  so  much  as  a  phenomenon  of 
mobilization  of  fat  deposit  as  of  the  cellular  lipoids  and  as 
evidence  of  increased  cellular  disintegration.63  Other  ob- 
servers do  not  express  themselves  upon  this  point  in  by  any 
means  as  dogmatic  a  manner.  Thus  an  examination  of  the 
blood  in  a  case  of  pancreatic  diabetes   showed  that  the 

60  F.  N.  Schulz,  Pflüger's  Arch.,  65,  299,  1897;  W.  Daddi  (W.  Aducco's 
Lab.) ,  Lo  Sperimentale,  52,  43,  1898. 

C1L.  Lattes  (Turin),  Arch.  f.  exper.  Pathol.,  66,  132,  1911,  and  earlier 
investigators. 

62  L.  Schwarz  (Prague),  Deutsch.  Arch.  f.  klin.  Med.,  76,  233,  1903; 
G.  Klemperer  and  H.  Umber,  Zeitschr.  f.  klin.  Med.,  61,  145,  1907;   65,  340,  1908. 

03  G.  Klemperer,  Deutsch,  med.  Wochenschr.,  1910,  2373. 


374  DIGESTION  AND  RESORPTION  OF  FATS 

lecithin  was,  as  a  rule,  increased,  but  the  amount  of  Choles- 
terine was  variable;64  another  observer  on  the  contrary 
believes  that  in  the  lipaeniia  of  human  diabetes  we  are  deal- 
ing more  with  a  cholesterinaemia  than  with  a  lecithinaemia.65 
The  writer,  too,  regards  it  as  more  than  doubtful  whether  an 
accumulation  of  as  much  as  half  a  kilogram  or  more,  as  esti- 
mated by  Magnus-Levy,66  in  the  circulating  blood  in  nu- 
merous coma  cases,  can  be  properly  referred  to  the  lipoids 
arising  from  cellular  disintegration.  As  there  is  every  rea- 
son to  regard  the  acetone  bodies  to  be  due  to  changes  in  the 
neutral  fat,  it  would  appear  not  at  all  inappropriate  to  refer 
the  coincident  lipaemia  to  the  same  basic  cause.  That  tissue 
cells  do  undergo  disintegration  and  that  their  lipoids  gain 
access  to  the  circulating  blood  under  such  circumstances 
should  not,  it  seems,  be  a  matter  of  doubt. 

Lipcemia  from  Narcosis. — Beicher's  suggestion  that  in 
the  lipaemia  which  is  sometimes  seen  in  long  continued  anaes- 
thetization  we  are  dealing  with  an  escape  of  lipoids  from 
the  cells  (due  to  entrance  of  fat  solvents  in  the  blood)  is 
contradicted  by  the  fact  that  lipaemia  is  sometimes  also  seen 
in  morphine  narcosis  where  such  an  outpouring  cannot  be 
considered.67 

On  reflection,  moreover,  it  must  be  confessed  that  in- 
creased passage  of  fat  into  the  blood  stream  does  not  en- 
tirely explain  the  pathological  lipaemias.  It  should  be 
recalled  that  even  the  greatest  concentration  of  fat  in  the 
blood,  as  that  which  takes  place  after  ingestion  of  fatty 
food,  disappears  under  normal  circumstances  in  the  course 
of  a  few  hours,  the  fat  leaving  the  blood  stream.  It  was 
formerly  believed  to  be  due  to  the  tissue  cells  taking  up  the 
haemoconial  particles ;  yet  it  may  be  presumed  that  at  least 
in  part  the  fat  passes  through  the  capillary  walls  in  dis- 

64  J.  Seo  (Minkowski's  Clinic,  Greifswald),  Arch.  f.  exper.  Pathol.,  61, 
1,  1909. 

05  M.  Adler  (Univ.  Polyclinic,  Berlin),  Berliner  klin.  Wochenschr.,  1909, 
1453. 

86  A.  Magnus-Levy  and  L.  F.  Meyer,  1.  c,  p.  464. 

eT  Cf.  A.  Magnus-Levy  and  L.  F.  Meyer,  1.  c,  p.  463. 


PASSAGE  OF  FAT  OUT  OF  BLOOD  STREAM        375 

solved  state.  The  liver  undoubtedly  performs  an  important 
role  in  working  up  the  fat  which  passes  out  of  the  circulat- 
ing blood.08  Observations  of  K.  Glässner  and  G.  Singer 
on  animals  with  biliary  fistulas  indicate  that  the  fat  of  the 
food  passes  to  the  liver  by  way  of  the  blood,  is  fixed  there 
for  a  brief  period  and  may  also  be  in  part  excreted  in  the 
bile.69 

Passage  of  the  Fat  Out  of  the  Blood  Stream. — But  when 
it  is  realized  that  in  pathological  lipaemia  large  quantities  of 
fat  continue  in  concentration  in  the  blood,  the  logical  con- 
clusion must  necessarily  be  that  for  some  reason  or  other 
the  fat  must  be  hindered  in  its  passage  out  of  the  circulating 
blood.  There  is  not  the  least  basis  for  accepting  the  idea 
that  the  parenchymatous  tissues  because  of  loss  of  oxidizing 
power  have  been  deprived  of  their  ability  to  consume  fat  in 
their  normal  manner.  As  Magnus-Levy  properly  suggests, 
it  is  impossible  to  consider  anything  except  some  added  diffi- 
culty of  passage  of  the  fat  out  of  the  capillaries,  either  from 
change  in  the  permeability  of  the  capillary  walls  or  from 
delay  in  the  occurrence  of  the  changes  which  are  necessary 
in  the  fat  itself  in  order  to  enable  it  to  pass  through  the 
capillary  wall.70  What  the  nature  of  such  changes  is  it  is 
impossible  to  say  at  present. 

Brief  reference  may  here  be  made  to  the  question  as  to 
what  conditions  are  required  for  the  passage  of  the  fat  from 
the  blood  into  the  urine.  There  is  no  doubt  that  in  condi- 
tions of  concentration  of  fat  in  the  blood  small  amounts  of 
the  former  may  pass  over  into  the  urine.71  Both  lipuria 
and  albuminuria  have  been  induced  coincidently  by  infusion 
of  cream  intravenously  in  the  dog,  the  fat  appearing  in  the 
urine  as  a  persistent  cloud-like  emulsion.72    Massive  occur- 

68  F.  Ramond,  Jour,  de  Physiol.,  7,  245,  1905. 

69  K.  Glässner  and  G.  Singer  (E.  Freund's  Lab.,  Vienna),  Med.  Klinik, 
1909,  No.  51. 

70  A.  Magnus-Levy  and  L.  F.  Meyer,  1.  c,  p.  465. 

71  B.  Schöndorff  (Physiol.  Instit.,  Bonn),  Pflüger's  Arch.,  117,  291,  1907: 
cf.  therein  the  Literature. 

"A.  Magnus-Levy  and  L.  F.  Meyer.  1.  c..  p.  469. 


376  DIGESTION  AND  RESORPTION  OF  FATS 

rence  of  fat  in  the  urine  ("chyluria")  is  only  observed,  as 
indicated  beyond  doubt  by  recent  studies,73  when  there 
happens  to  be  an  abnormal  communication  between  the  chyle 
vessels  and  the  urinary  passages. 

Fetal  Lipcemia. — An  interesting  form  of  lipaemia  has  been 
observed  in  fetal  guinea  pigs  by  A.  Kreidl  and  his  col- 
laborators. It  seems  that  the  blood  of  developed  guinea 
pig  fcetuses  is  crowded  with  ultramicroscopic  particles  of 
fat.  Their  presence  is  in  no  way  due  to  corpuscular  fat 
contained  in  the  maternal  blood ;  the  placenta  prevents  the 
corpuscular  fat  in  the  maternal  circulation  from  passing  to 
the  foetus,  and  vice  versa.  In  the  end,  of  course,  the  foetus 
obtains  its  required  fat  from  the  mother  animal,  and  it  must 
be  assumed,  therefore,  that  the  component  fatty  acids  and 
glycerol  are  taken  from  the  maternal  blood,  synthesized  by 
the  placenta  into  fat  and  transmitted  as  such  to  the  foetus. 
The  placenta  in  this  matter  seems  to  fulfil  a  function  similar 
to  that  which  belongs  to  the  secreting  mammary  gland74 
(v.  infra,  Chapter  XVII).  In  human  beings  during  preg- 
nancy the  blood  becomes  richer  in  fatty  substances  (espe- 
cially Cholesterine  compounds  and  neutral  fat).75  The 
proportion  of  lipoids  in  the  placenta  is  maximal  in  the  early 
stages  of  pregnancy  and  diminishes  during  the  course  of 
the  period.76 

Peculiar  features  in  the  migration  of  fat  may  be  met  in 
many  fish,  as  in  the  torpedo,  the  female  of  which,  according 
to  Reach,  does  not  take  food  during  her  pregnancy,  her  rich 
supply  of  hepatic  fat  passing  into  the  yolks  to  serve  as  the 
most  important  source  of  energy  for  the  embryos.77 

73  Carter,  Franz  and  Steyskal,  Magnus-Levy ;  Literature :  A.  Magnus-Levy 
and  L.  F.  Meyer,  1.  c,  469-470. 

74  Oshima  (under  direction  of  A.  Kreidl,  Vienna),  Centralbl.  f.  Physiol.,  21, 
No.  10,  1907;  A.  Kreidl  and  H.  Donath,  ibid.,  2k,  No.  1,  1910. 

76  E.  Herrmann  and  J.  Neumann  (S.  Fränkel's  Lab.,  Vienna),  Wiener  klin. 
Wochenschr.,  1912,  No.  12,  and  Biochem.  Zeitschr.,  k3,  47,  1912. 

78  B.  Bienenfeld  (S.  Fränkel's  Lab.  and  F.  Schauta's  Clinic,  Vienna), 
Biochem.  Zeitschr.,  JfS,  245,  1912,  and  Monatschr.  f.  Geburtsh.,  36,  158,  1912. 

77  F.  Reach,  in  collaboration  with  V.  Widakowich  (A.  Durig's  Lab.,  Vienna) , 
Biochem.  Zeitschr.,  40,  128,  1912. 


PAVY'S  THEORY  377 

Diet  Lipcemia. — In  detailing  the  different  forms  of 
lipaemia  mention  must  finally  be  made  of  mastlipasmia,  seen, 
for  instance,  in  geese  sometimes  after  forced  carbohydrate 
feeding  and  after  fatty  diet.78  It  may,  perhaps,  be  imagined 
that  when  there  is  too  great  a  transformation  of  carbohy- 
drates into  fat,  the  fat  depots  become  overfilled  to  snch  an 
extent  that  finally  they  can  no  longer  accommodate  it,  and 
that  then  it  accumulates  in  the  blood.  It  may  be,  too,  that 
the  lipaemia  of  many  obese  alcoholics  can  be  referred  to  a 
similar  mode  of  causation  (v.  infra,  p.  387). 

Pavy's  Theory. — Pavy 79  observed  that  if  rabbits  are  fed 
upon  material  rich  in  carbohydrates  but  poor  in  fat,  as 
oats,  the  intestinal  chyle  vessels  afterwards  become  promi- 
nent from  their  milk-white  injection.  On  this  fact  he  based 
his  theory  (diametrically  opposed  to  all  of  our  views)  that 
the  intestinal  villi  are  able  to  change  carbohydrate  into  fat, 
and  that  this  happens  with  the  most  of  the  resorbed  carbo- 
hydrates so  that  they  do  not  enter  the  blood  as  sugar. 
Gr.  von  Bergmann  and  K.  Keicher  were,  however,  able  to 
prove  that,  on  feeding  with  oats  from  which  the  fat  had  been 
carefully  extracted,  no  fat  appears  either  in  the  intestinal 
villi  or  in  the  lymph  vessels,  and  that  therefore  Pavy's 
hypothesis  is  not  correct.80 

The  path  to  knowledge  is  paved  with  mistakes ;  this  has 
always  been  so  and  always  will  be.  Whoever  has  devoted 
himself  for  any  time  to  experimental  study  leams  from  his 
own  failures  to  be  lenient  toward  the  failures  of  others. 
And  yet  one  cannot  help  feeling  depressed  to  see,  as  in  this 
instance,  some  new  theory  brought  before  the  world  which 
upsets  all  existing  opinions  and  brings  about  a  lot  of  con- 
fusion, when  even  a  simple  and  obvious  control  examination 
would  have  been  sufficient  to  prevent  its  birth. 

78  Bleibtreu,  Pflüger's  Arch.,  85,  345,  1901. 

79  F.  W.  Pavy,  Ueber  den  Kohlehydratstoffwechsel,  Leipzig,  Engelmann, 
1907. 

80  G.  v.  Bergmann  and  K.  Reicher  (F.  Kraus's  Clinic,  Berlin),  Zeitschr.. 
f.  exper.  Pathol.,  5,  760,  1909. 


CHAPTER  XVI 
FAT  METABOLISM.     OBESITY 

Having  discussed  the  manner  in  which  the  food  fat  is 
taken  up  from  the  intestine,  how  it  enters  the  blood  and  is 
distributed  with  the  latter  in  the  body,  we  may  next  endeavor 
to  gain  some  insight  into  the  methods  by  which,  having 
accumulated  in  the  economy,  it  is  transformed  in  metabolism. 

We  should  start  with  the  fact  that  fat  serves  as  an 
important  source  of  energy  and  is  a  substance  well  suited 
to  limit  the  demand  upon  other  materials.  In  contrast  to 
protein  it  is  strikingly  distinguished  by  its  capacity  for  being 
stored  as  a  reserve  substance  in  times  of  abundant  supply; 
while,  as  is  well  known,  we  are  not  directly  in  position  to  in- 
sure a  new  formation  of  organized  body-protein  by  an 
abundant  proteid  food  supply. 

Dependence  of  Protein  Destruction  Upon  Supply  of  Fat. 
— When  protein  and  fat  are  ingested  at  the  same  time  the 
amount  of  protein  required  can  be  kept  down  by  the  latter. 
While  (following  the  teachings  of  the  Voit  school)  in  a  dog 
fed  on  proteid  material  alone  the  nitrogen  balance  can  be 
maintained  only  by  supplying  three  and  one-half  times  the 
amount  of  protein  exchanged  in  inanition,  the  nitrogen 
balance  may  be  successfully  maintained,  if  fat  be  also  ex- 
hibited, with  but  one  and  a  half  or  two  times  the  amount  of 
protein  metabolized  in  starvation.  At  first  glance  the  state- 
ment based  on  Voit 's  authority  that  in  a  starving  dog,  whose 
fat  deposits  have  not  as  yet  been  consumed,  administration 
of  several  hundred  grams  of  fat  scarcely  influences  the 
protein  exchange  at  all,  seems  surprising.  The  explanation 
of  this  rather  remarkable  peculiarity  is  simply  that  in  star- 
vation fat  is  in  demand  also ;  as  already  stated,  the  starving 
body  draws  mainly  upon  fat  to  supply  its  requirements  for 
production  of  energy.  If,  therefore,  a  starving  organism, 
which  still  has  a  supply  of  fat,  be  flooded  with  fat,  this  added 
fat  will  be  surely  burned  in  place  of  the  tissue  fat,  but  will 

378 


PARENTERAL  FAT  ABSORPTION  379 

not  otherwise  make  much  change  in  the  relative  transforma- 
tion processes.  Above  all,  however,  the  wear  on  the  cor- 
poreal mechanism  will  be  manifest  in  a  nearly  constant 
nitrogenous  output.1 

Importance  of  Lipoids  in  Nutrition. — Is  fat  a  vitally  nec- 
essary food?  We  formerly  were  disposed  to  deny  this  ques- 
tion without  hesitation,  because  it  was  well  known  that  dogs 
can  be  readily  kept  alive  and  strong  for  a  long  time  on  meat 
diet  alone.  However,  recently  W.  Stepp,  in.  investigations, 
undertaken  under  direction  of  Franz  Hofmeister,  has 
brought  out  the  remarkable  fact  that  mice  invariably  die  if 
their  appropriate  food  be  freed  of  all  fatty  substances  by 
thorough  alcohol-ether  extraction.  If  pure  neutral  fat  (tri- 
palmitin,  tristearin  or  triolein),  or  lecithin  or  cholesterol  or 
even  butter,  be  added  to  the  degreased  food,  the  animals  con- 
tinue to  die;  apparently  it  is  not  the  well-defined  fats  but 
certain  " lipoids"  which  are  essential  for  maintenance  of 
life.  This  is  only  another  example  of  the  peculiar  things 
which  one  is  sure  to  encounter  in  the  course  of  metabolism 
studies.2 

Parenteral  Fat  Absorption. — If  it  is  desired  to  introduce 
large  amounts  of  fat  into  the  body  apparently  the  only  way 
is  by  the  bowel,  and,  perhaps,  too,  by  intraperitoneal  intro- 
duction. Experimental  subcutaneous  injection  of  olive  oil, 
and,  similarly,  stained  and  iodized  fat,  has  invariably  shown 
that  only  very  small  amounts  of  such  substances  (at  best  no 
more  than  a  few  grams  per  diem)  can  be  absorbed  from  the 
subcutaneous  tissue,  the  bulk  otherwise  remaining  unchanged 
in  situ.  On  reflection  it  may  be  readily  appreciated  that  the 
injected  fat  in  all  likelihood  (just  as  the  fat  of  the  organized 
depots)  can  be  absorbed  only  after  it  has  been  changed  to  a 
soluble  form  by  some  lipolytic  ferment.    However,  a  large 

1  Literature:  Graham  Lusk,  Ernährung  and  Stoffwechsel,  2d  ed.  (German 
Translation  by  L.  Hess),  pp.  149-154,  1910. 

2W.  Stepp  (Hofmeister's  Lab.,  Strassburg),  Biochem.  Zeitschr.,  22,  452, 
1909;  Zeitschr.  f.  Biol.,  57,  135,  1911.  Cf.  also  W.  Stepp  (Med.  Clinic,  Giessen, 
Voit),  XXIX  Kongr.  f.  innere  Med.,  Wiesbaden,  1912,  p.  610. 


380  FAT  METABOLISM.    OBESITY 

amount  of  fat  injected  under  the  skin  presents,  of  course,  a 
relatively  small  surface  for  attack  by  such  ferments,  and  for 
this  reason  it  seems  possible  to  very  materially  improve  the 
resorption  by  introducing  the  fat  in  the  form  of  a  fixed  emul- 
sion. In  spite  of  the  fact  that  in  occasional  experiments  it 
has  seemed  possible  to  distinctly  prolong  the  life  of  starving 
animals  by  subcutaneous  injections  of  fat,  the  hopes  which 
were  entertained  by  clinicians  of  being  able  to  feed  by  sub- 
cutaneous injection  of  fat,  because  fat  contains  in  the 
smallest  volume  the  largest  amount  of  energy  (measured  in 
calories),  have  for  the  present  at  least  entirely  failed  of 
realization23  (v.  infra,  Chapter  XX). 

Fat Storageinthe Body. — The  amount  of  fat  stored  in  the 
economy  is  very  considerable  even  under  normal  conditions. 
In  a  healthy  human  being  it  has  been  estimated  at  about  18 
per  cent,  of  the  body-weight.  The  importance  of  the  energy 
thus  accumulated  can  be  readily  appreciated  when  one  thinks 
of  the  long  periods  of  fasting  and  the  diseases  which  can  be 
endured  in  which  the  intake  of  food  seems  to  be  reduced  to  a 
minimum.  A  study  made  in  Pflüger 's  laboratory3  showed 
in  a  well  nourished  dog  a  fat  content  equivalent  to  more  than 
one-fourth  of  its  body  weight ;  about  one-half  of  the  fat  was 
obtained  from  the  skin  and  subcutaneous  tissue,  and  one- 
third  from  the  musculature,  so  that  only  a  comparatively 
small  proportion  was  distributed  in  the  other  tissues.  In  a 
fattened  animal  as  much  as  a  third  or  even  a  half  of  the  live 
weight  may  be  represented  by  fat.  The  large  quantities  of 
glycogen  which  the  liver  ordinarily  contains  during  full  car- 
bohydrate diet,  are  supplanted  by  fat  in  case  of  forced 
feeding  with  the  latter,  thus  bringing  out  the  antagonism 

2aW.  v.  Leube,  1895;  E.  Koll,  1898;  Hofbauer,  1903;  H.  Winternitz,  1903 
and  1906.  Literature :  A.  Magnus-Levy  and  L.  F.  Meyer,  Handb.  d.  Biochem.,  If, 
448-449,  1909;  and  E.  Heilner  (Munich),  Zeitscbr.  f.  Biol.,  5-'h  54.  1910. 
J.  Henderson  and  E.  F.  Crofutt  (Yale  Med.  School) ,  Amer.  Jour,  of  Physiol.,  Ik, 
193,  1905. 

3  K.  Möckel,  Pftiiger's  Arch.,  108,  189,  1905. 


DEPOSIT  OF  FOREIGN  FAT  381 

which  was  above  mentioned  between  glycogen  and  fat.4 
Pflüger  found  in  a  dog  which  had  been  fed  solely  upon  large 
quantities  of  fat  for  a  month,  that  all  of  the  glycogen  had 
been  replaced  in  the  liver  by  fat,  which  comprised  almost 
half  of  the  dried  hepatic  substance.5  From  the  readiness 
with  which  the  economy  is  able  to  draw  upon  its  fat  supply 
in  case  of  need,  it  is  remarkable  with  what  tenacity  a 
residuum  of  the  fat  is  retained.  According  to  F.  N.  Schulz 6 
the  external  appearance  alone  of  a  starved  dog  affords  no 
basis  for  judging  the  amount  of  fat  in  its  economy,  and  mere 
long  continuance  of  starvation  is  not  sufficient  to  actually 
make  an  animal  free  of  fat. 

Deposit  of  Foreign  Fat. — We  may  now  take  up  more  fully 
the  question  of  the  manner  in  which  the  economy  makes  use 
of  the  food  fat. 

A  long  series  of  experiments  have  proved  that  the  body 
can  lay  down  foreign  types  of  fat  in  its  own  depots.  It  has 
been  shown  that  oil  of  rape,  linseed  oil,  oil  of  sesame,  mutton 
suet  and  cow's  butter  are  not  only  deposited  in  the  system, 
but  that  foreign  types  of  fat  may  also  find  their  way  into 
milk,  eggs  and  the  coccygeal  secretion  of  birds.7  Iodized 
and  bromized  fats  can  also  be  laid  down  in  the  body,  as 
shown  by  the  studies  of  Winternitz,  Coronedi  and  others.8 

For  a  long  time  no  more  doubt  has  been  entertained  as 

*A.  Magnus-Levy,  Noorden's  Handb.  d.  Path.  d.  Stoffw.,  2d  ed.,  1,  177, 
1906,  regards  the  antagonism  between  glycogen  and  fat  accumulation  in  the 
liver  as  not  an  absolute  one;  he  states  that  he  has  frequently  found  in  typical 
examples  of  fois  gras  of  Strassburg  geese  very  large  deposits  of  glycogen  along 
with  enormous  quantities  of  fat. 

0  Cf.  also  Pflüger  and  E.  Junkersdorf,  ibid.,  131,  225,  1910. 

"F.  N.  Schulz  (Pflüger's  Lab.),  Pflüger's  Arch,  66,  145,  1897. 

7  Radziejewski,  Lebedeff,  J.  Munk,  Leube,  G.  Rosenfeld,  Winternitz,  Cas- 
pari,  Zaitschek,  Röhmann,  Henriques  and  Hansen;  Literature:  G.  Rosenfeld, 
Ergebn.  d.  Physiol.,  1",  673-678,  1902;  A.  Magnus-Levy,  Noorden's  Handb.  d. 
Pathol,  d.  Stoffw.,  2d  ed.,  1,  178,  1906. 

8  G.  Coronedi  and  R.  Luzzatto,  Arch,  di  Farmacol.,  12,  343,  cited  in  Cen- 
tralbl.  f.  Physiol.,  21,  122,  1907;  cf.  G.  Coronedi  (Parma),  VIII  Intern.  Physiol. 
Congr.,  Vienna,  Sept.,  1910;  G.  Coronedi  and  F.  Dematheis,  Boll,  della  Societä 
med.  di  Parma.,  July,  1911. 


382  FAT  METABOLISM.    OBESITY 

to  the  reality  of  assimilation  of  foreign  fats.  However,  it  is 
not  well  known  even  at  present  to  what  degree  the  body 
changes  this  acquired  fat,  and,  as  it  were,  impresses  upon  it 
the  stamp  of  its  own  individuality.  We  know,  it  is  true,  that 
the  fats  of  different  genera  of  animals  present  nearly  con- 
stant characteristics.  As  far  as  the  fat  which  is  formed 
within  the  body  (probably  from  carbohydrates)  is  con- 
cerned, there  is  nothing  remarkable  in  this.  But  in  case  of 
the  fat  which  is  acquired  directly  from  the  food,  this  would 
demand  a  constancy  in  the  food  which  certainly  does  not 
always  obtain  (providing  the  fat  does  not  undergo  secondary 
changes).  G.  Eosenfeld  found,  as  a  matter  of  fact,  that  a 
dog  which  had  been  stuffed  with  mutton  suet  continued  a 
month  after  interrupting  the  fat  diet  to  show  a  pure  mutton 
fat  in  his  tissues ;  and  he  was  of  the  opinion  that  a  panther, 
for  instance,  if  he  would  devour  nothing  but  sheep  would 
necessarily  put  on  sheep  fat.  He  found,  too,  that  gold  fish 
and  carp  when  fed  mutton  suet  deposit  this  form  of  fat; 
and  comparison  of  the  fats  of  various  marine  forms  with  the 
fats  of  their  customary  foods  showed  a  widespread  similar- 
ity between  them.  The  same  seems  to  be  true,  too,  for 
vegetarian  animals,  although  in  these,  besides  the  fats  con- 
tained in  the  food,  there  is  also  that  which  is  formed  in  the 
economy  from  carbohydrates.  "Thus  we  find,"  says 
G.  Eosenfeld,9  "that  the  herbivorous  animals  have  a  firm 
fat,  poor  in  oleic  acid,  while  the  graminivora  have  a  soft  fat. 
The  fat  of  the  food  shows  almost  precisely  the  same  char- 
acteristics ;  green  food  has  a  firm  fat,  seeds  contain  a  soft 
oil.  If  a  horse  becomes  fat  from  feeding  on  oats,  his  fat  will 
be  fluid;  if  he  has  been  fattened  on  hay,  his  fat  is  much 
firmer.  The  similarity  of  the  tallow  from  the  ox,  sheep,  roe 
and  hart  is  referable  to  the  similarity  of  food,  i.e.,  grasses." 
Transformation  of  Fat  in  the  Body. — Be  these  discov- 
eries as  illuminating  as  they  may,  we  have,  however,  no  sub- 
stantial reason  for  doubting  the  ability  of  the  body  to  adapt 

9 1.  c,  p.  676. 


SCLEREMA  NEONATORUM  383 

the  acquired  fats  to  its  own  requirements  by  certain  changes. 
Such  changes  may  include  more  rapid  absorption  of  oleic 
acid,  elimination  of  volatile  fatty  acids,  change  of  saturated 
into  unsaturated  fatty  acids  or  the  reverse,  or  of  the  latter 
into  oxy acids,  or  separation  of  the  long  carbon  chains  into 
shorter  groups,  etc. 

Thus,  for  example,  after  cramming  a  dog  with  butter 
which  is  characterized  by  its  high  proportion  of  volatile  fatty 
acids,  the  Reichert-Meiszl  figure  (which  is  indicative  of  the 
amount  of  the  latter  substances)  was  not  found  higher  in  the 
fat  of  the  animal  than  under  normal  conditions.10 

As  an  example  of  such  an  adaptation  process  may  per- 
haps be  pointed  out  that  in  infancy  the  proportion  of  oleic 
acid  in  the  dermal  fat,  as  stated  by  Knöpfelmacher  and 
LehndorfT,11  increases  from  month  to  month,  and  that  the 
buccal  fat  (which  acts  as  a  support  to  the  buccinator  muscle 
and  prevents  aspiration  of  the  poorly  developed  muscle  be- 
tween the  jaws  in  the  oral  negative  pressure  in  suction) 
seemingly  is  poorer  in  oleic  acid,  and  therefore  more  resis- 
tant than  the  general  subcutaneous  fat  tissue  of  the  same 
individual.  The  skin  fat  of  children  fed  upon  human  milk 
is  always  richer  in  unsaturated  fatty  acids,  than  that  of 
artificially  fed  infants.  When  an  infant  undergoes  emacia- 
tion the  proportion  of  oleic  acid  of  its  fat  decreases,  and  it 
appears,  according  to  Knöpfelmacher 's  studies,  that  the  in- 
flexibility of  the  fat  tissue  thus  induced,  which  is  poor  in 
oleic  acid,  is  related  with  the  condition  which  is  well  known 
by  podiatrists  under  the  name  sclerema  neonatorum.12 

Comparing  the  iodine  combining  power  of  yolk  fat  and 
that  of  the  fat  of  the  embryo  chick  in  course  of  development 


10  W.  v.  Leube,  Verhandl.  d.  Kongr.  f.  innere  Med.,  IS,  424,  1895. 

11 W.  Knöpfelmacher  and  H.  Lehndorff,  Zeitschr.  f.  exper.  Path.,  2,  133, 
1906;  H.  Lehndorff  (Abt.  Knöpfelmacher),  Jahrb.  f.  Kinderheilkunde,  66,  286, 
1907. 

"Literature  upon  Sclerema:  Cf.  F.  Luithlen,  Die  Zellgewebsverhärtung 
der  Neugeborenen,  Vienna,  Alfred  Holder,  1912;  G.  Rommel,  in  Hand.  d. 
Kinderheilk.,  1,  423-425,  1910. 


384  FAT  METABOLISM.     OBESITY 

within  the  egg,  the  fact  has  been  noted  that  the  former 
gradually  grows  poor  in  unsaturated  acids,  corresponding 
with  the  greater  mobility  and  resorption  of  oleic  acid  (in 
contrast  to  stearic  and  palmitic  acids).  On  the  other  hand, 
the  gradual  increase  in  the  iodine  value  of  the  organized  fat 
of  the  embryo  chick  indicate  that  saturated  acids  in  the 
embryo  are  undergoing  conversion  into  unsaturated  acids 
(v.  inf.).13 

Depot  Fat  and  Cell  Fat. — According  to  studies  of  Abder- 
halden and  Brahm  it  would  be  well  in  the  study  of  fat 
metabolism  to  distinguish  between  depot-fat  and  cell-fat. 
In  order  to  determine  whether  not  only  the  former  but  also 
the  fat  directly  involved  in  the  construction  of  the  body  cells 
is  dependent  upon  the  character  of  the  food  fat  ingested, 
dogs  were  fed  for  a  long  time  with  mutton  suet  or  with 
rape-seed  oil  and  then  killed.  The  readily  extracted  depot-fat 
is  then  removed  by  ether.  In  order  to  make  it  possible  to 
extract  the  cell-fat,  however,  the  tissue  to  be  subjected  to 
ether  is  digested  or  broken  up  by  dilute  hydrochloric  acid. 
It  is  interesting  to  note  from  this  procedure  that  the  proper 
cell-fat  in  contrast  to  the  depot-fat  is  independent  of  the 
character  of  the  ingested  food.14 

This  difference  between  depot-fat  and  cell-fat  acquires 
special  significance  when  it  is  recognized  that  a  considerable 
fraction  of  the  ethereal  extract  from  the  liver,  heart,  kidneys 
and  other  tissues  does  not  consist  of  ordinary  neutral  fat 
but  of  phosphatides  of  many  types  (v.  Vol.  I  of  this  series, 
pp.  171-172,  Chemistry  of  the  Tissues),  which  contain  be- 
sides the  typical  high  fatty  acids  even  a  higher  proportion 
of  unsaturated  fatty  acids  of  the  linseed  oil  and  linolic  acid 
series.15     There  is  perhaps  some  connection  between  the  fact 

13  E.  C.  Eaves  ( Instit.  of  Physiol.,  Univ.  College,  London ) ,  Jour,  of  Physiol., 
40,  No.  6,  1910. 

u  E.  Abderhalden  and  C.  Brahm,  Zeitschr.  f.  physiol.  Chem.,  65,  330,  1909. 

*5  Rubow,  Heffter,  Henriques  and  Hansen,  Erlandsen,  Hartley,  Leathea 
and  Kennaway  and  others.  Literature:  J.  B.  Leathes,  Ergebn.  d.  Physiol., 
8,  366-370,  1909. 


OXIDATIVE  FUNCTION  OF  LIVER  385 

that  these  acids  undergo  oxidation  very  readily  in  the  air 
with  loss  of  iodine-binding  power  and  the  further  fact  that 
Röhmann  16  and  his  collaborators  found  the  acetyl  propor- 
tions of  the  mixture  of  fatty  acids  obtained  from  the  liver 
extracts  distinctly  higher  than  those  of  the  fat  from  adipose 
tissue;  the  acetyl  figure  (the  number  of  milligrams  of 
potassium  hydrate  which  are  combined  with  the  amount  of 
acetic  acid  in  one  gram  of  acetylized  fat  after  saponification 
with  alcoholic  solution  of  potassium  hydrate)  is  a  well-known 
measure  for  the  amount  of  free  hydroxyl  groups  in  a  fat.  It 
seems  that  unsaturated  acids  are  to  be  found  in  tissues  not 
only  in  the  form  of  lecithids  and  Phosphatids  but  also  in  the 
form  of  simple  glycerides. 

Oxidative  Function  of  the  Liver  in  the  Catabolism  of 
Higher  Fatty  Acids. — These  results  acquire  special  signifi- 
cance from  the  observations  of  G.  Joannovics  and  E.  P.  Pick, 
and,  too,  of  Loathes  and  Hartley,  indicating  that  the  liver 
upon  access  of  fat  with  the  food  subjects  it  to  an  oxidation 
catabolism  with  formation  of  high  unsaturated  acids.  The 
first  mentioned  investigators  were  able  to  reduce  this  oxida- 
tion power  in  the  living  animal  by  narcotics.  It  might  well 
be  imagined,  perhaps,  that  by  the  introduction  of  new  double 
combinations  into  the  long  carbon  chain  the  fatty  acids  would 
be  prepared  for  their  oxidative  destruction,  these  double 
combinations  forming  points  of  lessened  resistance  at  which 
the  chains  may  be  separated  into  shorter  fragments,  the  lat- 
ter then  in  turn  undergoing  further  disintegration.17  The 
essential  features  of  the  subject  are  not  proven,  however,  as 
yet.  In  this  connection  the  passage  of  fat  to  the  liver  might 
from  one  standpoint  be  interpreted  on  the  supposition  that 

1SF.  Röhmann,  with  W.  Lummert,  Y.  Nukada,  Pfliiger's  Arch.,  11,  176, 
1898;  Biochem.  Zeitschr.,  llh  419,  1908. 

17  G.  Joannovics  and  E.  P.  Pick  (Instit.  Paltauf,  Vienna),  Wiener  klin. 
Wochenschr.,  1910,  573;  Pfliiger's  Arch.,  UfO,  327,  1911;  J.  B.  Leathes,  1.  c; 
J.  B.  Leathes  and  L.  Meyer- Wedell,  Journ.  of  Physiol.,  38,  Proc.  Physiol  Soc. 
XXXVIII,  1909;  P.  Hartley  (Lab.  of  J.  B.  Leathes),  Jour,  of  Physiol.,  88, 
353,  1909;  H.  Mottram,  Jour,  of  Physiol.,  3S,  281,  1909. 

25 


386  FAT  METABOLISM.     OBESITY 

the  higher  fatty  acids  (as  Nasse  has  suggested)  are  there 
prepared  for  further  elaboration;  on  the  other  hand,  as 
Magnus-Levy  believes,  the  accumulation  of  fat  in  the  liver 
may  be  an  expression  of  a  duty  ascribed  to  this  organ  of  hold- 
ing in  readiness  reserve  material  available  for  any  suddenly 
introduced  increase  of  metabolic  exchange.  "  It  is  evident 
that  finely  divided  fat  can  be  passed  when  needed  into  the 
blood  much  more  readily  and  quickly  from  the  liver  with  its 
full  vascular  arrangement,  than  from  the  fat  globules  of  the 
adipose  cells  of  the  subcutaneous  tissue,  which  present  so 
small  a  surface  in  proportion  to  their  contents.  According 
to  this  view  the  liver  with  its  deposits  both  of  glycogen  and 
of  fat  would  have  the  office  of  providing  material  for  combus- 
tion for  the  body  at  any  time  when  there  is  a  sudden  increase 
of  demand  put  upon  it. "  18 

Formation  of  Fat  from  Sugar. — A  matter  of  much  impor- 
tance to  the  physiological  procedure  of  metabolism  is  the 
formation  of  fat  from  sugar.  This  subject  may  now  be 
somewhat  more  fully  considered  as  the  reverse  process,  the 
formation  of  sugar  from  fat,  has  been  discussed  above 
(v.  supra,  p.  240). 

The  fact  that  carbohydrate  is  converted  into  fat  in  the 
economy  seems  today  quite  axiomatic  to  us ;  it  is  in  fact  one 
of  the  few  scientific  points  in  physiological  chemistry  which 
has  passed  into  popular  knowledge.  Every  layman  realizes 
in  these  days  that  people  who  want  to  avoid  becoming  too 
obese  must  guard  against  eating  too  much  bread  and  made 
dishes.  And  yet  it  was  at  the  expense  of  long  continued  and 
difficult  metabolic  study  that  the  fact  of  the  formation  of  fat 
from  sugar  was  finally  removed  from  any  doubt.19     The 

18  A  Magnus-Levy,  Noorden's  Handb.  d.  Pathol,  d.  Stoffwechs.,  2d  ed.,  1, 
177-178,  1906. 

"Literature  upon  Fat  Formation  from  Carbohydrates:  G.  Rosenfeld, 
Ergebn.  d.  Physiol.,  1,  666-671,  1902;  R.  Tigerstedt,  Nagel's  Handb.  d.  Physiol. 
1,  513-516,  1905;  A.  Magnus-Levy,  Noorden's  Handb.  d.  Pathol,  d.  Stoffwechs., 
2d  ed.,  1,  165-168,  1906;  A.  Magnus-Levy  and  L.  F.  Meyer,  Handb.  d.  Biochem., 
4,  449-450,  455-456,  472-474,  1909. 


TRANSFORMATION  OF  FAT  INTO  CARBOHYDRATE    387 

absolute  proof  was  attained  by  forced  feeding  of  various 
experiment  animals,  like  pigs,  sheep,  dogs,  and  geese,  on  fat- 
free  food,  poor  in  protein  but  rich  in  carbohydrates,  after  a 
previous  fasting.  Careful  equilibrium  experiments  showed 
that  large  amounts  of  carbon  are  retained  in  the  body.  That 
this  was  not  retained  in  the  form  of  protein  carbon  was 
proved  by  calculating  the  retained  nitrogen.  Even  granting 
that  a  high  proportion  of  glycogen  could  be  accepted  as 
accumulated  by  the  process,  there  still  remained  a  large  over- 
plus of  carbon  which  could  not  be  accounted  for  save  as 
representing  new-formed  fat. 

The  conversion  of  carbohydrate  into  fat  is  shown  in 
respiration  experiments  by  a  marked  rise  of  the  respiratory 
quotient.  Sugar  being  rich  in  oxygen  and  fat  poor  in  oxygen, 
transformation  of  the  former  into  the  latter  will  set  free 
considerable  oxygen  which  may  be  used  to  burn  carbon  into 
carbonic  acid.  This  will  lead  to  an  increase  in  the  numerator 
of  the  ratio  between  the  exhaled  carbonic  acid  and  the  inhaled 

CO 
oxygen,  — 2  •  the  amount  of  C02  eliminated  increases  with- 
out increase  of  the  oxygen  inhaled.  Thus  Bleibtreu  noted,  in 
case  of  geese  stuffed  with  carbohydrates,  and  Pembrey  in 
marmots,  which  were  preparing  for  hibernation  and  taking 
on  a  large  supply  of  fat  by  gorging  with  carbohydrates,  in 
order  to  enable  themselves  to  pass  the  winter  a  respiratory 
coefficient  which  reached  nearly  1.4.  This  amounts  to  almost 
double  the  proportion  to  be  met  in  a  normally  fed  individual. 
Transformation  of  Fat  into  Carbohydrate  in  the  Vege- 
table Economy. — For  the  most  part  in  these  lectures  it  is 
unfortunately  impossible  to  bring  forward  the  analogies 
which  exist  between  the  metabolism  of  animals  and  plants. 
In  the  present  connection,  however,  attention  should  be  called 
to  the  fact  that  the  plant  economy  is  likewise  able  to  change 
carbohydrate  into  fat  and  vice  versa.  While,  for  example, 
unripe  oily  seeds  contain  much  starch  and  mannite,  as  they 
ripen  the  carbohydrate  is  converted  into  oil.   However,  the 


388  FAT  METABOLISM.    OBESITY 

reverse  takes  place  when  oil-bearing  seeds  come  to  sprout,20 
the  oil  being  converted  in  greater  part  into  carbohydate, 
going  directly  as  it  disappears  from  the  reserve  stock  into  the 
formation  of  material  from  which  the  cell  walls  of  the  young 
plants  are  constructed.  Many  bulbs  and,  too,  ever-green 
leaves,  and  even  wood,  may  contain  reserve  fats.  In  many 
trees  starch  disappears  from  the  wood  in  winter,  consider- 
able amounts  of  fat  taking  its  place ;  in  the  spring  there  is  a 
return  of  the  fat  into  carbohydrate,  and  the  process  may 
be  to  a  certain  degree  reversed  by  artificial  chilling. 

Characteristics  of  Fat  which  is  Formed  de  novo  from 
Carbohydrates. — The  fat  formed  de  novo  in  the  animal  body 
from  carbohydrate  is  characterized  by  its  low  proportion  of 
oleic  acid  and  its  peculiar  firmness.  G.  Eosenfeld  found 
that  nine-tenths  of  the  fat  of  fasting  geese  consisted  of  oil, 
with  only  a  trace  of  solid  fat  in  it;  the  fat  of  geese  which 
had  been  fed  freely  on  potatoes  was,  however,  of  a  distinctly 
firmer  consistence  (very  like  lard),  which  did  not  become 
soft  at  full  summer  heat  and  when  tried  out  consisted  for 
the  most  part  of  crystals  of  palmitic  acid  and  stearic  acid 
glycerides,  with  which  only  a  small  amount  of  fluid  fat  was 
mixed.  In  mirror  carp,  too,  which  were  freely  fed  on  seeds 
in  a  bowl,  the  engorgement  with  carbohydrate  led  to  a  fat 
poor  in  oleic  acid.21  If  the  same  conditions  obtain  in  man, 
there  ought  to  be  a  distinct  difference  observable  between 
the  adipose  layer  of  Esquimaux,  who  assimilate  the  fluid 
fat  of  the  north  polar  animals,  and  that  of  a  negro  or  China- 
man in  whom  free  rice  diet  has  helped  to  produce  a  well 
developed  panniculus  adiposus;  and  this  may  well  have 
some  physiological  significance.  For  instance,  it  may  be 
readily  thought  that  an  individual  with  fat  containing  con- 
siderable oleic  acid  would  be  in  position  to  more  rapidly 
mobilize  his  fat  supply  than  one  in  whom  the  firm  fats  pre- 
vail.    Perhaps  there  is  some  difference  whether  a  child  as- 


30 Literature:    O.  v.  Fürth,  Hofmeister's  Beitr.,  4,  430,  1903. 
21  G.  Rosenfeld,  Ergebn.  d.  Physiol.,  V,  670,  1902. 


PLACE  OF  FAT  FORMATION  389 

similates  the  fluid  fat  of  codliver  oil  or  the  firm  fat  of  cow's 
butter.  We  have  little  positive  information  on  these  points ; 
but  it  would  undoubtedly  be  worth  while  for  the  podiatrists 
especially  to  devote  some  attention  to  the  subject.  Refer- 
ence  has  already  been  made  to  the  observation  that  the 
wasting  of  young  individuals  leads  to  an  impoverishment 
of  the  subcutaneous  fat  in  oleic  acid.  May  not  the  well- 
proved  favorable  influence  of  codliver  oil,  aside  from  its 
very  real  food  value,  be  possibly  dependent  upon  the  fact 
that  it,  in  the  absence  of  fat  depots,  serves  to  supply  fluid 
and  easily  absorbed  fatty  acids? 

Place  of  Origin  of  the  Fat  from  Carbohydrates. — An- 
other important  question  is,  in  what  tissues  is  the  fat  formed 
from  carbohydrates.  One  is,  of  course,  first  likely  to  think 
of  the  liver.  Gr.  Rosenfeld,  however,  concludes  from  results 
obtained  by  Bleibtreu  with  geese  stuffed  with  carbohydrate 
food,  in  some  of  which  the  blood  remained  poor  in  fat,  that 
if  the  carbohydrate  fat  is  actually  formed  in  the  liver  and 
thence  worked  into  the  subcutaneous  depot  the  migration  of 
the  fat  would  necessarily  always  be  recognizable  by  an  in- 
crease in  the  amount  of  fat  in  the  blood.  Arguing  in  this 
wise  Rosenfeld  finds  himself  forced  to  the  hypothesis  that 
fat  is  constructed  from  carbohydrate  at  the  place  of  its 
deposit,  therefore  especially  in  the  fat  cells  of  the  sub- 
cutaneous tissue.22  "While  normally  the  adipose  tissue  of 
rabbits  is  free  from  glycogen,  it  has  been  shown  that  after 
free  carbohydrate  nutrition  microscopic  examination  will 
reveal  a  marked  amount  of  glycogen  in  this  situation ;  but 
after  continued  forced  feeding  of  carbohydrates  the  glyco- 
gen after  a  time  disappears  from  the  fat  cells.23  Magnus- 
Levy  believes  that  the  interpretation  that  this  is  an  evidence 

22  G.  Rosenfeld,  1.  c,  p.  671. 

23  Gierke  (Freiburg),  Verb.,  d.  Pathol.  Gesellscb.,  1906,  182;  Best,  ibid., 
184. 


390  FAT  METABOLISM.    OBESITY 

of  formation  of  fat  from  carbohydrate  is  probably  correct, 
even  though  further  study  is  necessary.24 

Chemistry  of  Fat  Formation  from  Sugar. — The  problem 
of  the  chemical  transformations  by  which  sugar  is  converted 
into  fat  has  as  yet  not  passed  beyond  the  hypothetical  stage. 
The  fact  that  the  high  fatty  acids  concerned  in  the  synthetic 
production  of  fat  show  an  even  number  of  carbon  atoms  sug- 
gests the  idea  that  groups,  each  containing  two  carbon  atoms, 
may,  perhaps,  be  concerned  in  the  construction  of  the  long 
chains.  In  review  of  hypotheses  of  Nencki  and  Hoppe- 
Seyler,  Magnus-Levy  suggests  25  that  the  formation  of  fat 
from  sugar  may  take  place  along  the  same  lines  as  {v.  supra., 
p.  347)  the  bacterial  butyric  acid  fermentation,  that  is,  by 
way  of  lactic  acid  and  acetaldehyde.26  As  is  well  known,  two 
molecules  of  lactic  acid  may  be  derived  from  one  molecule  of 
sugar,  C6H1206  =  2  C3H603;   the  latter,  then,  by  oxidation 

CH3  CH, 

gives  rise  to  acetaldehyde,   CH.OH  +  O    =   COH  +  co2  +  H,o. 

COOH 

This  under  certain  condensation  conditions  is  changed  into 

CH, 
CH3  +  CH,      =      CH.OH 

a  four  chain  group,  aldol :  \    ^    ^         ^H       •  It  has  been 

COH 

proved,  moreover,  that  two  molecules  of  this  latter  substance 
may  be  condensed  in  vitro  into  an  eight-carbon  atom  group : 

CH,  CH, 

CH.OH  +  CH.OH  =  CH,-CH(OH)-CH,-CH(OH)-CH,-CH(OH).CH,.COH. 

CH2  CH2 

COH  COH 

The  conversion  of  this  last  in  the  laboratory  into  n.  octylic 
acid,  CH3.CH2.CH2.CH2.CH2.CH2.CH2.COOH,  is  easily  ac- 


24  A.  Magnus-Levy  and  L.  F.  Meyer,  1.  c,  p.  456. 

25  A.  Magnus-Levy  and  L.  F.  Meyer,  1.  c.,  pp.  472-474. 

20  A.  Magnus-Levy,  Verhandl.  d.  physiol.  Ges.,  Berlin,  March  15,  1902,  etc. 


DISINTEGRATION  OF  FAT  391 

complished.27  Finally  it  is  undoubtedly  rational  to  suppose 
that  the  aldol  by  taking  up  one  atom  of  oxygen  may  change 

CH3  CHj 

CH.OH  +  O  =  CH.OH  . 

into  /?-oxybutyric  acid :   l  .   This,  however, 

CH,  CHS 

COH  COOH 

undoubtedly  plays  an  important  role  in  the  physiological 
chemistry  of  the  fatty  acids,  to  which  further  reference  will 
be  made  in  a  succeeding  lecture.  However,  it  may  well  be 
that  the  route  from  sugar  to  fat  may  be  quite  different,  and 
may  not  lead  through  lactic  acid  and  aldehyde.  Even  to- 
day it  is  still  impossible  to  speak  at  all  positively  in  this 
connection. 

In  precisely  the  same  way  as  the  upbuilding  of  the  long 
carbon  chain  of  the  fatty  acid  molecule  is  shrouded  in  dark- 
ness, so,  too,  is  its  catabolism  unknown.  As  no  opportunity 
seems  open  in  the  study  of  animal  metabolism  to  solve  this 
mystery  the  writer  has  endeavored  by  two  experiments  in 
the  field  of  plant  physiology  to  force  an  access. 

Experiments  upon  the  Disintegration  of  Fat  by  Plants. — 
In  the  first  place  the  writer,  at  the  suggestion  of  his  teacher, 
Franz  Hofmeister,  took  up  the  behavior  of  the  fat  of  oil- 
bearing  seeds  at  time  of  sprouting  (v.  supra,  p.  387)  in  order, 
if  possible,  to  obtain  from  the  study  of  their  fat  catabolism 
some  basic  information  applicable  to  the  chemistry  of  the 
conversion  of  fat  in  the  animal  body.  In  spite  of  all  the 
care  with  which  large  numbers  of  sun-flower  and  castor-bean 
seedlings  were  reared  in  the  basement  of  the  Strassburg 
Institute,  it  was  impossible  to  find  in  them  any  trace  of 
intermediate  products  between  fat  and  sugar,  or  to  de- 
termine in  a  single  instance  the  new  formation  of  unsatur- 
ated acids  or  oxy-acids  of  the  fatty  acid  series.28 

27  Raper,  Jour.  Chem.  Soc,  91,  1831,  1907;  Proc.  Chem.  Soc,  23,  235,  1907, 
cited  in  Chem.  Centralbl.,  1908',  223. 

25  0.  v.  Fürth  (F.  Hofmeister's  Lab.),  Hofmeister's  Beitr.,  ll,  430,  1903. 


392  FAT  METABOLISM.    OBESITY 

There  was  not  much  more  success  when  later  with  his 
friend,  Carl  Schwarz,  the  writer  undertook  to  study  the 
disintegration  of  fat  by  low  forms  of  plant  life  (mould- 
fungi,  bacillus  fluorescens  liquefaciens,  proteus).29  The 
microorganisms  were  watched  in  their  growth  and  develop- 
ment upon  inorganic  media  containing  as  their  sole  organic 
substance  high  fatty  acids,  and  in  their  abstraction  of  their 
carbon  requirements  from  these  fatty  acids ;  but  the  investi- 
gators never  succeeded  in  obtaining  any  catabolic  product. 
The  only  point  that  was  learned  was  that  this  type  of  fat 
catabolism  cannot  be  regarded,  as  is  occasionally  done,  as 
parallel  to  any  of  the  known  fermentation  processes.  To  all 
appearances  it  is  rather  an  intracellular  oxidation  process. 

Catabolism  of  the  Fatty  Acids  in  the  Animal  Body. — The 
most  available  points  of  attack  for  the  type  of  catabolism  of 
the  higher  fatty  acids  which  occurs  in  the  economy  are  pre- 
sented from  the  studies  of  F.  Knoop  30  on  the  one  hand,  and 
by  those  of  Gr.  Embden31  and  his  associates  on  the  other, 
somewhat  as  follows :  The  catabolism  of  the  saturated  ali- 
phatic fatty  acids  takes  place  by  oxidation  at  the  ß-carbon 
atom  with  cleavage  of  the  two  carbon  atoms  from  the  car- 
boxyl end : 

CHz— CH2— CHr- CH2— CH2— COOH 

CHj—  CH2— CHo— CH(OH)— CH2— COOH 

CH2— CH2— CH2— COOH 

CH2— CH(OH)— CH2— COOH 

CHa— COOH. 

Embden  held  that,  in  case  the  process  actually  takes  place  in 
the  manner  depicted,  it  would  be  necessary  to  expect  that 
eventually  from  the  higher  fatty  acids,  after  the  long  carbon 
atom  chain  is  again  and  again  shortened  by  throwing  off  two 

28  O.  v.  Fürth  and  C.  Schwarz  (Festschr.  f.  Giulio  Fano) ,  Archivio  di  Fisiol., 
7,  441,  1909. 

30  F.  Knoop,  Hofmeister's  Beitr.,  6,  150,  1905. 

31 G.  Embden,  H.  Salomon  and  Fr.  Schmidt,  Hofmeister's  Beitr.,  8,  129, 
1906;    G.  Embden  and  A.  Marx,  Hofmeister's  Beitr.,  9,  318,  1908. 


CATABOLISM  OF  FATTY  ACIDS  393 

carbon  atoms,  we  would  obtain  butyric  acid  and  from  this 
ß-oxybutyric  acid,  diacetic  acid  and  acetone : 


BUTYRIC   ACID 

/S-OXYBTJTYRIC 

DIACETIC 

ACETONE 

ACID 

ACID 

CH3 

CH3 

CH3 

I 

CHOH 

1 

CH3 

CH2 

CO 

1 

— >• 

1          — * 

CH2 

CO  +  co2 

CH2 

CH2 

CH3 

COOH 

1 
COOH 

COOH 

There  follows  now  the  very  interesting  fact  that  if  various 
acids  are  added  to  the  blood  perfused  through  the  living 
excised  liver  of  a  dog,  the  acids  with  even  number  of  carbon 
atoms  (butyric  acid,  C4 ;  caproic  acid,  C6 ;  caprylic  acid,  C8 ; 
capric  acid,  C10)  give  rise  to  a  notable  acetone  formation; 
while  in  case  of  the  acids  with  uneven  number  of  carbon 
atoms  the  amounts  of  acetone  formed  are  no  greater  than 
when  the  liver  is  perfused  with  normal  blood.  Embden32 
properly  says  that  the  supposition  that  fatty  acid  catabolism 
takes  place  in  the  manner  described  has  been  made  much 
more  probable  by  these  experiments.  It  should  be  definitely 
understood  that,  provided  the  oxidation  of  a  carbon  chain  in 
the  body  takes  place  at  the  /?-carbon  atom  (as  we  have  every 
reason  for  assuming,  following  Knoop)  we  can  never  obtain 
from  a  normal  fatty  acid  with  an  uneven  number  of  carbon 
atoms  /3-oxybutyric  acid  and  acetone ;  for  example : 

CH,  CH, 


CH2  CH,  CH,.OH 


CH, 

CH2  — ►•         CH.OH       — >-         CH2  — >■        CH2 

CH2  CH2  COOH  COOH. 

I  I 

COOH  COOH 

Eeference  will  again  be  made  to  these  points,  which  argue 
a  direct  relation  between  the  acetone  bodies  and  fat  disinte- 
gration in  the  economy,  when  the  former  are  discussed.  Con- 
sideration of  the  occurrence  of  the  lower  fatty  acids  in  milk 

*3  G.  Embden  and  A.  Marx,  1.  c. 


394  FAT  METABOLISM.    OBESITY 

will  also  give  occasion  to  take  up  the  matter  of  fatty  acid 
catabolism.  It  should  only  be  added  that  Dakin,33  who 
hoped  to  imitate  the  oxidation  reactions  in  the  body  by  the 
action  of  hydrogen  peroxide,  observed  besides  the  oxida- 
tion at  the  ß-carbon  atom  the  same  thing  at  the  a-atom  and 
the  catabolism  of  the  ß-oxybutyric  acid  into  not  only  diacetic 
acid  and  acetone  but  also  into  acetic  acid  and  formic  acid: 


CHj.CHCOEO.CH, 

j.COOH 

jS 

Sk 

CH,.CO.CH2.COOH 

CH,.COOH 

\ 

\ 

CHj.CO.CO,  +  COa 

H.COOH  +  CO, 

\ 

C02  +  H20. 

Whether  an  analogous  disintegration,  as  this  just  described, 
is  also  to  be  thought  of  as  physiological,  is,  however,  at  pres- 
ent not  known. 

Nature  of  Obesity. — Here  may  be  taken  up  briefly  what 
is  known  from  the  standpoint  of  the  biochemist  of  the  nature 
of  obesity. 

Common  experience  indicates  that  many  persons  who  are 
" disposed"  toward  corpulence  accumulate  fat  even  though 
they  do  not  ingest  any  more  food  apparently  than  do  other 
individuals ;  in  such  cases  one  might  suspect  that  there  exists 
a  lowering  of  material  exchange.  A  whole  series  of  studies 
upon  metabolism  in  obesity  are  now  at  our  disposal  for 
consideration.34  Many  authorities,  as  Jaquet  and  Svenson, 
found,  as  a  matter  of  fact,  in  corpulent  persons  a  distinctly 
lower  increase  in  gas-interchange  after  ingestion  of  food 

33 H.  D.  Dakin  (C.  A.  Herter's  Lab.,  New  York),  Jour,  of  biol.  Chem.,  kf 
77,  91,  227,  1908. 

"Thiele  and  Nehring,  1896;  Stuve,  1896;  A.  Magnus-Levy,  1897;  C.  von 
Noorden,  1900;  Jaquet  and  Svenson,  1900 ;  Rubner,  1902;  Reach,  1904;  E.  A. 
v.  Willebrandt,  1908;  R.  Stähelin,  1909;  G.  v.  Bergmann,  1909;  F.  Umber, 
1909.  Literature  on  Metabolism  in  Obesity:  C.  v.  Noorden,  Die  Fettsucht, 
Nothnagels  Handb.,  Part  7,  1900;  v.  Noorden's  Handb.  d.  Pathol,  d.  Stoffw., 
2d  ed.,  2,  189-211,  1907;  A.  Jaquet,  Ergebn.  d.  Physiol.,  2',  553-554,  1903; 
F.  Umber,  Lehrb.  d.  Ernähr,  u.  d.  Stoffwechselkr.,  73-117,  1909;  G.  von  Berg- 
mann, Handb.  d.  Biochem.,  4"  208-237,  1910. 


NATURE  OF  OBESITY  395 

than  in  normal  individuals ;  the  reaction,  too,  was  of  abnor- 
mally short  duration,  the  gas  interchange  sinking  to  normal 
within  two  or  three  hours  after  taking  food.  They  regarded 
the  conclusion  justifiable  that  the  obese  individual  must 
necessarily  as  a  result  of  diminished  interchange  be  storing 
his  combustible  material.  Observation  of  Reach,  Stähelin 
and  Gr.  v.  Bergmann  also  indicated  that  at  least  many  corpu- 
lent persons  differ  from  normal  persons  particularly  in  that 
their  curve  of  interchange  does  not  rise  as  high  and  descends 
less  sharply  to  a  level  after  intake  of  food,  in  such  manner 
that  a ' '  trailing  out  of  metabolism ' '  is  suggested.  However, 
these  positive  statements  are  completely  contradicted  by 
those  of  other  authorities.  Thus  Rubner 35  compared  with 
the  greatest  care  the  metabolism  of  two  brothers,  both  child- 
ren and  differing  only  a  single  year  in  age,  one  of  whom  was 
corpulent,  the  other  spare.  Calculated  according  to  the 
square  surface,  the  exchange  in  the  two  was  exactly  the  same, 
and  there  could  not  be  considered  any  specific  diminution  of 
metabolism.  We  cannot  off  hand,  therefore,  ascribe  to  all 
obese  persons  a  diminished  protoplasmic  disintegration 
energy;  on  the  contrary  we  may  be  forced  to  assume,  fol- 
lowing Rubner,  apparently  for  the  majority  of  them  just  as 
much  utilization  of  energy  in  relation  to  their  body  mass  as 
would  correspond  to  an  equivalent  normal  individual.36 
A.  Loewy  and  F.  Hirschfeld  also  find  that  there  are  normal, 
in  fact  lean,  persons  in  whom  the  maintenance  exchange 
is  so  low  that  it  may  be  of  the  same  level  at  least  as  the 
interchange  determined  in  individual  cases  of  obesity.  Per- 
haps it  would  be  best  to  foresee,  if  the  expression  may  be 
permitted,  that  the  methods  of  investigation  now  at  our 
command  are  not  good  enough  to  allow  us  to  say  that  there 
is  a  true  and  constant  abnormality  in  the  metabolism  of  all 
obese  individuals ;  which  does  not  say,  however,  that  such 
fault  does  not  exist. 

35  Rubner,  Beiträge  zur  Ernähr,  im  Kindesalter,  Berlin,  1902. 
3*  Cf .  F.  Umber,  1.  c,  pp.  78  and  84. 


396  FAT  METABOLISM.    OBESITY 

Corpulence  and  Overfeeding. — For  the  rest,  it  should  be 
understood  that  we  can  explain  very  well  (even  in  persons 
who  are  not  customarily  large  eaters)  an  accumulation  of 
fat  by  the  summation  of  very  small  amounts  of  food  beyond 
the  maintenance  requirements.  Carl  von  Noorden37  illus- 
trates this  point  by  the  following  proposition:  A  healthy 
man  weighing  70  kilograms,  who  uses  40  calories  for  each 
kilogram  per  diem,  in  all,  therefore,  2,800  calories,  will  gen- 
erally regulate  his  intake  of  food  involuntarily  according  to 
the  actual  requirements  of  his  body ;  and  is  able  thus,  even 
with  entirely  free  choice  of  food,  to  keep  himself  in  average 
state  of  nutrition  for  many  years.  A  small  daily  excess  of 
food  of  only  200  calories  will  result,  if  we  presume  that  it  is 
converted  into  fat  and  deposited  as  such,  in  a  yearly  gain  in 
weight  of  eleven  kilograms.  One  would  be  surprised  to  learn 
to  how  small  a  quantity  of  food  these  200  calories  corre- 
spond :  1/3  liter  of  milk,  or  4/10  liter  of  light  beer,  or  90 
grams  of  rye  bread,  or  25  grams  of  butter,  or  100  grams  of 
fat  meat.  What  fat  man  would  dare  then  to  disclaim  the 
possibility  with  quiet  conscience  that  at  least  at  times  he  has 
not  been  guilty  of  overeating? 

Moreover,  if  this  is  to  be  properly  appreciated,  we  must 
also  take  into  account  the  relation  between  "ballast"  and 
"live  substance"  in  the  body.  "The  relation  between  bal- 
last and  live  substance, ' '  says  H.  Friedländer,  ' '  is  variable 
in  individuals  at  different  periods  of  age.  .  .  .  Abnor- 
mally fat  animals,  like  whales  and  seals,  as  well  as  ab- 
normally fat  men,  contain  to  the  unit  of  weight  less  active 
substance  than  lean  animals  of  the  same  age  period;  the 
complaint  of  many  fat  persons  can  be  understood  when  they 
declare  that  they  continue  to  put  on  weight  with  an  absolutely 
lower  ingestion  of  food.  In  ratio  to  their  small  proportion 
of  live  substance  the  ingested  food  is  frequently  not  small, 
and  a  portion  of  it  is  still  available  for  weight  increment. ' ' 3S 

37  C.  von  Noorden,  Handb.  d.  Pathol,  d.  Stoffw.,  2d  ed.,  2,  190,  1907. 

38  H.  Friedenthal  (Nicholas  Lake  in  Berlin),  Centralbl.  f.  Physiol.,  23,  437, 
1909. 


ANTIFAT  TREATMENTS  397 

Antifat  Treatments. — It  is  impossible  to  enter  into  the 
various  antifat  treatments  39  beyond  mentioning  that  in  the 
majority  of  cases  they  are  essentially  fasting  treatments, 
with  different  variations.  Thus  in  the  so-called  Banting 
treatment  there  are  given,  mostly  in  form  of  meat,  only  about 
1100  calories  to  a  person  instead  of  the  2800  calories  due 
him ;  the  Ebstein  bill  of  fare  with  about  1300  calories  gives 
preference  to  fat ;  that  the  intermittent  restricted  milk  diet 
in  limited  amounts  is  equivalent  to  actual  fasting  goes  with- 
out saying.  The  same  thing  is  true  of  the  Rosenfeld  potato 
treatment  (with  about  1200  calories).  OertePs  treatment  is 
based  on  the  restriction  not  only  of  the  number  of  calories 
but  also  of  the  amount  of  fluid  allowed;  but  it  should  be 
remarked  that  the  losses  in  weight  obtained  with  this  last 
method,  for  which  the  patient  must  pay  with  the  torments 
of  thirst,  are  partly  only  apparent  and  are  due  to  the  loss  of 
water.  We  have  learned  to  realize,  too,  that  the  patient 
should  not  be  allowed  to  be  weakened  in  the  course  of  an 
antifat  treatment.  It  is  important  that  modern  methods 
of  dietetic  reduction  of  fat  be  so  planned,  like  that  of 
G.  Gärtner,  that  the  subjective  sensation  of  hunger  be  kept 
down  by  full  use  of  bulky  food  rich  in  cellulose,  of  low  caloric 
value,  like  green  vegetables  and  fruits.  It  is  of  value,  too, 
to  further  the  process  of  reduction  by  increasing  the  mus- 
cular activity.  Employment  of  mineral  waters  containing 
sodium  sulphate  (Marienbad,  Karlsbad,  Neuenahr,  Tarasp) 
often  is  of  service  by  lowering  the  complete  utilization  of  the 
food.  ' '  The  combined  action  of  all  the  factors  favoring  the 
reduction  of  fat  in  special  baths,"  says  F.  Umber,  "the 
regulation  of  diet  (which  is  frequently,  for  example  in  Ma- 
rienbad,  in  Kisch's  regulations,  administered  in  a  bill  of 
fare  similar  to  that  of  the  Banting  system),  the  drink  treat- 
ments, the  bath  treatments,  the  systematic  muscular  exer- 
cise, and  not  the  least  the  removal  of  the  patients  from  their 

38  For  details  cf.  E.  H.  Kisch,  Entfettungskuren,  Berlin,  1901 ;  F.  Umber, 
Lehrb.  d.  Ernährung  u.  Stoffwechselkr.,  1909,  pp.  94-114. 


398  FAT  METABOLISM.    OBESITY 

every-day  surroundings,  all  these  are  elements  which  make 
for  success  in  such  an  establishment  for  the  cure  of  the 
obese.  First  and  foremost  the  result  is  that  these  obese 
people,  who  either  are  unwilling  or  cannot  use  the  necessary 
energy  and  precaution  at  home  to  deal  with  their  trouble, 
amuse  themselves  with  the  annual  outcome  of  their  Marien- 
bad or  Kissingen  sojourn  and  make  excuses  for  their  per- 
sistent failings." 

The  thyroid  gland  medication  in  the  obese  depends  upon 
an  entirely  different  principle.  Gr.  von  Bergmann40  holds 
that  an  increase  of  calory-exchange  of  from  25  to  50  per 
cent,  can  be  obtained  by  administration  of  thyroid  sub- 
stance, with  protection  of  the  protein  store;  and  believes 
that  (if  we  exclude  direct  or  indirect  toxic  influences,  espe- 
cially upon  the  nervous  system,  which  may  give  rise  to 
contraindication  for  this  method  of  treatment)  thyroid 
gland  substance  is  "from  a  purely  metabolic  standpoint  the 
ideal  means  of  reducing  fat."  As  has  been  previously 
stated  (Vol.  I  of  this  series,  p.  450,  Chemistry  of  the  Tissues), 
we  cannot  fully  share  this  view,  and  are  more  likely  to  accept 
the  idea  (on  the  basis  of  the  statements  of  Magnus-Levy, 
Ebstein,  v.  Noorden,  Umber  and  others)  that  the  antifat 
treatments  by  administration  of  thyroid  not  only  are  want- 
ing in  every  practical  but  also  every  physiological 
justification. 

Fattening. — In  conclusion  of  the  present  discussion  we 
may  point  out  what  principles  are  involved  if  the  opposite 
of  the  above  depicted  effect  is  sought  to  be  obtained,  namely, 
putting  on  fat.  Probably  nothing  better  can  be  done  than  to 
follow  herein  the  lines  of  thought  which  C.  von  Noorden  has 
developed  in  his  remarkable  monograph  concerning  hyper- 
nutrition.41 

40  G.  v.  Bergmann,  Handb.  d.  Biochem.,  4",  230-237,  1910. 
a  C.  von  Noorden,  "  Die  Ueberernährung,"  Handb.  d.  Pathol,  des  Stoffw.,  2d 
ed.,  1,  548-577,  1906. 


FATTENING  399 

A  sharp  difference  must  be  drawn  between  fattening  and 
putting  on  flesh. 

There  are  undoubtedly  cases  in  which  a  true  protein  up- 
building takes  place ;  this  is  seen,  for  example,  in  the  period 
of  growth,  during  pregnancy,  in  functional  hypertrophy  of 
the  muscles  from  exercise,  and  above  all  in  convalescence 
after  sickness  and  undernutrition.  In  correspondence  to  an 
increased  intake  of  food,  which  (in  contrast  to  the  normal  of 
40  calories  per  diem  for  each  kilogram  of  body  weight)  may 
reach  as  much  as  70  calories  in  the  first  weeks,  the  energy 
exchange,  for  example,  in  a  convalescent  from  typhoid  fever 
may  be  found  tremendously  exaggerated  (30  to  50  per  cent.). 
The  respiratory  quotient  remains  generally  in  the  neigh- 
borhood of  1,  as  the  energy  expenditure  is  chiefly  made  good 
by  combustion  of  carbohydrates,  while  the  fat  and  protein 
are  not  burned  but  accumulate  in  the  economy. 

The  usual  fattening,  as,  for  instance,  that  which  is  prac- 
tised in  such  large  measures  by  animal  raisers,  is  truly  a 
putting  on  of  fat.  The  production  of  well-muscled  animals 
with  large  amount  of  meat  is  not  possible  by  forced  feeding, 
but  only  by  selective  breeding  (a  proposition  which  has 
suffered  scarcely  any  check  from  occasional  observations 
which  have  been  made  upon  nitrogen  retention  after  feed- 
ing abnormally  large  amounts  of  protein).  Besides  fat, 
water  may  also  contribute  to  an  important  degree  to  the 
on-put  of  weight  of  fattened  individuals.  This  is  observed, 
for  example,  in  the  very  marked  increase  of  weight  seen  at 
first  in  forced  feeding,  followed,  however,  by  a  pause;  at 
first  in  such  cases  there  is  a  marked  accumulation  of  water 
in  the  tissues,  which  is  thereafter  gradually,  with  rise  of 
diuresis,  replaced  by  fat. 

If  we  ask,  further,  what  type  of  food  may  be  expected 
to  be  followed  most  quickly  by  increase  of  fat,  the  answer 
would  be  that  protein  seems  least  suited,  as  an  excess  of 
calories  provided  in  protein  form  is  usually  not  fixed. 

The  carbohydrates  are  much  more  favorable;   there  is 


400  FAT  METABOLISM.    OBESITY 

always  lost  about  one-fourth  of  their  energy  value  in  passing 
from  the  intestine  to  the  fat  depots,  in  which,  according  to 
the  findings  of  N.  Zuntz  and  Eubner,  not  only  the  work  of  di- 
gestion but  also  the  heat  abstraction  which  takes  place  in 
the  passage  of  carbohydrate  into  fat,  are  included. 

"The  most  favorable  substance  is  fat"  says  Carl  von 
Noorden.  "This  requires  but  little  expenditure  of  force 
on  the  part  of  the  digestive  organs  and  is  deposited  as  fat 
with  almost  no  loss  of  energy.  Practical  medicine  still  hesi- 
tates to  make  effective  use  of  fat  as  a  fattening  medium,  and 
generally  gives  preference  to  the  carbohydrates.  I  have 
often  pointed  out  that  this  should  be  abandoned,  and  that 
large,  and  even  enormous  amounts  of  fat  (neglecting  here 
certain  pathological  changes  of  the  stomach  and  intestines) 
are  excellently  borne,  and  bring  about  results  which  can 
scarcely  be  equalled,  not  to  say  surpassed,  by  extra  adminis- 
tration of  carbohydrates. ' ' 

Alcohol,  too,  may  find  a  place  among  the  adjuvants  in 
fattening,  because  of  the  large  energy-value  it  possesses,  and 
because  its  combustion  serves  to  protect  other  material. 
However,  because  of  its  toxic  features  it  can  be  considered 
only  in  very  limited  sense  as  a  food  material;  and  is,  of 
course,  in  no  wise  indispensable  (as  has  been  thoroughly 
established).  The  writer  is,  however,  not  so  naive  as  to 
fancy  that  the  many  fellow  beings  whom  alcohol  serves  as  a 
fattening  agent  in  an  empiric  way  not  worthy  of  imitation 
will  allow  themselves  to  be  at  all  disturbed  in  the  use  of  this 
substance  by  considerations  of  a  physiological-chemical 
nature. 

Now  and  then  we  realize  to  our  surprise  that  practice 
does  not  always  direct  its  measures  as  theory  believes  is 
right. 

This  holds  good,  unfortunately,  not  only  for  alcohol,  but 
also  for  many  other  measures  looking  to  the  advance  of 
human  culture. 


CHAPTER  XVII 

FAT-SPLITTING   TISSUE   FERMENTS.    FAT  FORMATION 
FROM  PROTEIN.   FATTY  INFILTRATION  AND  FATTY 
DEGENERATION.    ORIGIN  OF  MILK-FAT. 
FAT-SPLITTING  TISSUE  FERMENTS 

From  the  general  knowledge  we  possess  as  to  the  fate 
of  fat  in  the  living  body  there  is  no  doubt  that  even  outside 
the  intestinal  tract  a  voluminous  catabolism  of  neutral  fat 
takes  place.  We  see  a  flood  of  fat  pouring  into  the  blood 
after  ingestion  of  fat-bearing  food,  and  after  a  time  dis- 
appearing; we  see  that  in  wasting  processes  the  fat  disap- 
pears from  its  depots  in  cells  and  tissues ;  we  notice  in  the 
processes  of  fat-migration  of  every  type  how  the  fat  is 
mobilized  in  the  compass  of  the  large  depots.  There  is 
certainly  probability  in  the  assumption  of  a  close  relation 
between  fat  mobilization  and  fat  cleavage  and  in  the  belief 
that,  just  as  the  stable  glycogen  passes  into  solution  as  soon 
as  the  economy  requires  it,  the  same  is  true  of  fat.  From 
what  has  been  said  it  might  be  supposed  that  the  fat,  which 
according  to  Pflüger  's  opinion  can  pass  from  the  intestine 
only  after  cleavage,  can  also  only  pass  through  the  wall  of 
the  blood  capillaries  when  in  fully  split  state,  as  soap.  Many 
authorities  have  earnestly  tried  to  attribute  it  to  the  cleav- 
age of  fat  in  the  blood  and  the  tissues.1 

Cleavage  of  Fat  in  the  Blood. — We  next  ask  ourselves 
what  is  there  in  the  proposition  of  fat  cleavage  in  the 
blood.  It  has  been  previously  stated  that  Hanriot,  when 
engaged  upon  the  subject,  came  to  the  conclusion  that  there 
exists  in  the  blood  a  lipolytic  ferment;  while  the  opponents 
of  this  view 2  were  of  the  opinion  that  at  most  there  is  an 

1  Literature  upon  Fat-splitting  Tissue  Ferments:  W.  Connstein,  Ergebn. 
d.  Physiol.,  S,  223-226,  1904;  H.  M.  Vernon,  Intracellular  Enzymes,  London, 
John  Murray,  pp.  53-60,  1908;  C.  Oppenheimer,  Die  Fermente,  3d  ed.,  5-24, 
1909;  F.  Samuely,  Handb.  d.  Biochem.,  533-537,  1909;  A.  Magnus-Levy  and 
L.  F.  Meyer,  ibid.,  4',  457,  1909. 

*Arthus,  Doyen  and  Morel. 
26  401 


402  FAT-SPLITTING  TISSUE  FERMENTS 

estersplitting  ferment  present,  but  no  lipase.  We  have  al- 
ready seen,  too,  that  the  apparent  disappearance  of  fat  from 
the  blood,  as  may  be  observed  in  vitro  (v.  supra,  p.  370) ,  is  due 
to  a  masking  of  the  fat  but  not  to  a  lipolysis.  In  the  course 
of  the  last  few  years  P.  Eona  and  L.  Michaelis 3  have  reverted 
to  the  question  of  cleavage  of  esters  and  fat  in  the  blood. 
They  start  out  from  the  fact  that  observation  of  the  surface 
tension  of  aqueous  solutions  of  glycerol  esters  permits  one 
to  follow  the  cleavage  of  these  substances  with  unusually 
marked  clearness ;  the  glycerolesters  of  the  lower  fatty  acids 
(in  contrast  to  their  cleavage  products)  belong  to  the  sub- 
stances having  very  marked  surface  activity  which  sharply 
lower  the  tension  of  water.  They  were  able  to  recognize, 
using  Traube  's  drop  counter,  the  presence  not  only  of  Han- 
riot 's  monobutyrin-splitting  ferment  but  also  of  a  tributyrin 
splitting  ferment  in  the  blood.  The  velocity  of  ester  cleav- 
age was  approximately  in  proportion  to  the  quantity  of  fer- 
ment.4 The  authors  named  speak  of  the  tributyrin-splitting 
ferment  as  a  "true  lipase,"  a  statement  which  is  perhaps 
entirely  correct  from  the  standpoint  of  physical  chemistry. 
Whether,  however,  this  lipase  is  of  importance  from  a 
physiological  point  of  view,  and  whether  it  is  actually  to  be 
considered  as  involved  in  the  cleavage  of  true  fat  can 
scarcely  be  regarded  as  proved.  An  observation  of  Abder- 
halden and  Eona  is  of  interest  here,  indicating  that  after 
feeding  large  amounts  of  specifically  foreign  fat  and,  too,  in 
starvation,  an  exaggeration  of  the  ester-splitting  power  be- 
comes noticeable  in  the  blood  of  dogs.5  That  the  serum 
lipase  cannot  be  held  to  be  simply  resorbed  pancreatic  lipase 
is  shown  by  the  points  that  it  is  not  materially  influenced  by 
removal  of  the  pancreas,  and  that  it  does  not  seem  to  be  at 

s  P.  Rona  and  L.  Michaelis  (Hospital  at  Urban,  Berlin) ,  Biochem.  Zeitschr., 
SI,  345,  1911. 

4  P.  Rona,  Biochem.  Zeitschr.,  33,  413,  1911;  P.  Rona  and  J.  Ebsen,  ibid., 
89,  20,  1912. 

5E.  Abderhalden  and  P.  Rona,  Zeitschr.  f.  physiol.  Chem.,  75,  30,  1911; 
E.  Abderhalden  and  A.  E.  Lampö,  ibid.,  78,  396,  1912. 


CLEAVAGE  OF  ESTERS  IN  THE  TISSUES  403 

all  activated,  as  the  pancreatic  lipase  is,  by  the  salts  of  the 
biliary  acids.6 

Lipase  of  the  Leucocytes. — In  the  cellular  elements  of  the 
blood,  too,  the  existence  of  a  lypolytic  ferment  has  been 
demonstrated,  not  only  by  ester-splitting  but  also  by  a  plate 
method,  somewhat  like  the  Müller-Jochmann  method.  Just 
as  in  the  latter  method  the  tryptic  power  of  cells  is  recog- 
nized by  the  formation  of  depressions  in  a  gelatine  plate, 
in  this  case  the  formation  of  delles  in  a  wax  plate  is  ob- 
served. Preparations,  consisting  mainly  of  lymphocytes, 
especially  tuberculous  pus,  show  fine  examples  of  delle- 
formation  dependent  upon  fat-cleavage.  Myeloid  cells  ap- 
parently do  not  contain  a  lipase.  If  capillary  tubes  filled 
with  yellow  wax  be  introduced  aseptically  into  the  peritoneal 
cavity  of  living  animals  examination  will  show  after  one  or 
two  days  that  at  the  open  ends  of  the  tubes  the  wax  will  have 
disappeared,  and  will  have  been  replaced  by  a  whitish  ma- 
terial consisting  principally  of  mononuclear  white  blood 
corpuscles.7 

In  this  connection  it  is  very  suggestive  that,  according 
to  observations  of  Edmund  Nirenstein,  infusoria  (par- 
amcecia)  are  not  only  capable  of  ingesting  large  amounts  of 
fat  from  an  emulsion  of  oil,  but  also  of  digesting  it  within 
the  food  vacuoles  (that  is,  decomposing  it  into  components 
soluble  in  water).8 

Cleavage  of  Esters  in  the  Tissues. — As  far  as  the  exist- 
ence of  lipolytic  ferments  in  tissues  is  concerned,  a  number 
of  statements  are  to  be  found  in  the  literature  concerning  the 
cleavage  of  different  esters  (as  monacetin,  monobutyrin, 
ethylbutyrate,  tribenzoin  and  amylsalicylate).    P.  Saxl,  who 

8  C.  L.  von  Hess  (Carlson's  Lab.,  Chicago),  Jour,  of  Biol.  Chem.,  10,  381, 
1911. 

T  S.  Bergel  (Surgical  Clin.,  Berlin),  Münchener  med.  Wochenschr.,  1909, 
H.  2;    N.  Fiessinger  and  P.  L.  Marie,  C.  R.  Soc.  de  Biol.,  67,  1909. 

8E.  Nirenstein  (II  Zoöl.  Instit.,  Vienna),  Zeitschr.  f.  allgemein.  Physiol., 
10,  137,  1909 ;  cf.  on  the  contrary  the  different  interpretation  of  W.  Staniewicz, 
Bull,  de  l'Acad.  de  Cracovie,  1910,  199,  cited  in  Centralbl.  f.  Physiol.,  24,  855, 
1910. 


404  FAT-SPLITTING  TISSUE  FERMENTS 

tried  out  these  statements  at  the  request  of  the  author,  found 
that  the  first  three  esters  above  named  are  split  in  only  very 
slight  but  always  measurable  degree  by  short  exposure  (an 
hour  at  room  temperature)  to  the  influence  of  minced  tissues 
(but  salicylic  acid  amylester  was  split  by  almost  all  the  tis- 
sues studied).  On  longer  exposure  to  the  same  influence 
usually  a  marked  access  of  acidity  could  be  recognized  titri- 
metrically,  brought  about  not  only  by  the  cleavage  of  the 
esters  but  also  by  formation  of  acid  by  autolysis  of  the  tis- 
sues. Saxl  came  to  the  conclusion  that  none  of  the  recom- 
mended methods  is  adapted  to  quantitative  study  of  ester 
cleavage,  and  that  all  the  statements  dealing  with  quantita- 
tive variations  of  lipase  in  the  tissues  are  without  proper 
foundation.9  P.  Rona  has  shown  that  tracing  the  change  in 
surface  tension  of  a  solution  of  monobutyrin  or  tributyrin 
may  also  be  employed  in  the  recognition  of  ester-splitting 
ferments  in  aqueous  extracts  of  tissues.10  But  this  method 
has  not  been  properly  elaborated  as  a  quantitative  one  any 
more  than  the  rest.  The  greatest  problem  in  this  connec- 
tion not  as  yet  solved,  and  perhaps  not  capable  of  solution, 
is  that  of  quantitative  extraction  of  the  lipases  from  a  tissue. 
Studies  upon  animal  and  plant  lipases  especially  have  raised 
reasonable  doubt  as  to  whether  the  lipases  are  at  all 
soluble  in  water  and  whether  they  are  separable  from  organ- 
ized cytoplasm.11  With  this  should  be  associated  the  strik- 
ing observation  that  the  ester-splitting  power  of  freshly 
prepared  tissue  extracts  becomes  enormously  augmented 
when  they  are  preserved  on  ice.12    All  in  all,  this  matter  is 

»P.  Saxl  (under  direction  of  0.  v.  Fürth),  Biochem.  Zeitschr.,  12,  343, 
1908;  consult  therein  the  older  Literature:  Hanriot,  P.  Th.  Müller,  Kastle  and 
Loevenhart,  R.  Magnus,  N.  Sieber;  cf.  also  L.  B.  Mendel  and  Leavenworth, 
Amer.  Jour,  of  Physiol.,  21,  95,  1908. 

10  P.  Bona,  Biochem.  Zeitschr.,  82,  482,  1911. 

"Astrid  and  Euler,  Hoyer,  Armstrong,  Nicloux,  cited  in  H.  M.  Vernon, 
1.  c,  p.  60;    L.  Breczeller  (Tangl's  Lab.),  Biochem.  Zeitschr.,  34,  170,  1911. 

"  M.  C.  Winternitz  and  R.  Meloy  ( Johns  Hopkins  Univ. ) ,  Jour.  Med. 
Research,  22,  107,  1910. 


FAT-SPLITTING  TISSUE  FERMENTS  405 

by  no  means,  to  the  writer's  way  of  thinking,  satisfactorily 
removed  from  the  plane  of  uncertainty. 

Fat-splitting  Tissue  Ferments. — This  feeling  of  uncer- 
tainty grows  when  we  come  to  consider  the  true  lipases,  that 
is,  those  tissue  ferments  which  bring  about  cleavage  of  neu- 
tral fats  into  their  components.  There  are  a  few  references 
in  literature  to  this  type  of  ferments.13  P.  Saxl,14  in  follow- 
ing these  up  in  control  tests,  obtained  results  indicating  that 
neutral  fat,  both  that  contained  in  the  tissues  and  that  added 
thereto  undergoes  but  a  slight  degree  of  cleavage  during 
postmortem  autolysis  (excluding  action  of  bacteria).  The 
author's  usual  contention,  however,  here  applied  to  Saxl's 
negative  findings,  would  rank  them  as  of  less  relative  value 
than  the  positive  results  of  other  authors,  who,  like  Umber 
and  Brugsch,15  Pagenstecher  16,  and  Berczeller,17  conducted 
their  experiments  carefully  and  added  the  fat  in  the  form 
of  an  emulsion  to  the  tissue  pulp.  In  experiments  of  this 
sort  it  is  likely,  too,  that  activation  of  zymogens  plays  an 
important  role.  Thus  in  the  adipose  tissue  of  freshly  killed 
hens  practically  no  lypolytic  power  can  be  detected;  but  it 
appears  after  they  are  kept  for  a  long  time.18  It  is  im- 
possible here  to  enter  in  detail  into  the  ferment-kinetics  of 
the  lipases ;  only  a  few  more  features  seemingly  essential  to 
a  sketch  of  their  characteristics,  may  be  briefly  mentioned. 

13Lüdy;  Ramond  (1889),  ]904;  N.  Sieber,  Zeitschr.  f.  physiol.  Chemie.,  55, 
177,  1908. 

"P.  Saxl,  1.  c;  cf.  also  G.  Comessati,  Clin.  Med.  Ital.,  46,  417,  cited  in 
Jahresber.  f.  Tierchem.,  38,  179,  1908. 

15  F.  Umber  and  Tli.  Brugsch,  Arch.  f.  exper.  Pathol.,  55,  164,  1906. 

16  A.  Pagenstecher  (Heidelberg),  Biochem.  Zeitschr.,  18,  285,  1908;  cf.  also 
A.  Juschtschenko  (St.  Petersburg),  Biochem.  Zeitschr.,  25,  49,  1910 ;  G.  Izar 
(Catania),  ibid.,  40,  390,  1912. 

17  L.  Berczeller  (F.  Tangl's  Lab.,  Budapesth),  Biochem.  Zeitschr.,  44,  185, 
1912. 

13  M.  E.  Pennington  and  J.  S.  Hepburn,  Jour.  Amer.  Chem.  Soc,  34,  210, 
1912;  United  States  Dept.  of  Agriculture,  Bureau  of  Chem.,  Circular  No.  75, 
1911,  cited  in  Centralbl.  f.  d.  ges.  Biol.,  13,  No.  5,  and  156,  1912. 


406  FORMATION  OF  FAT  FROM  PROTEIN 

Dakin's  observation  that  the  racemic  esters  of  mandelic 

acid,    |  are  asymmetrically  split  by  the  lipase 

CH(OH).COOH'  J      f  J  f 

from  hog's  liver  has  been  interpreted  to  mean  that  the 
enzyme  itself  is  an  optically  active  substance.19 

It  is  worth  noting,  too,  that  the  tissue  lipases,  just  as  the 
pancreatic  lipase,  may  be  activated  by  biliary  salts.20  More- 
over, the  fact  that  minute  amounts  of  acid  serve  to  activate 
a  tissue  lipase  of  vegetable  nature,  the  lipase  of  ricinus,  has 
proved  of  very  wide  practical  value  in  industrial  fat  cleav- 
age, based  on  the  studies  of  Connstein,  Hoyer  and  Water- 
berg.21  The  same  ferment,  which  brings  about  cleavage  of 
neutral  fat  in  the  presence  of  an  excess  of  water,  works 
in  the  reverse  fashion,  that  is,  to  cause  synthetic  formation 
of  neutral  fat,  when  allowed  to  act  upon  a  mixture  of  fatty 
acids  and  glycerol  in  a  medium  poor  in  water.22 

FORMATION  OF  FAT  FROM  PROTEIN.     FATTY   DEGENERA- 
TION AND  FATTY  INFILTRATION 

At  this  point  we  turn  to  a  difficult  and  complicated 
problem  which  has  had  a  prime  position  for  the  past  half 
century  in  the  interest  of  metabolic  physiologists  and  pathol- 
ogists, the  question  of  formation  of  fat  from  protein. 

The  doctrine  of  a  metamorphosis  of  protein  into  fat  takes 
its  starting-point  on  the  one  hand  from  E.  Virchow's  micro- 
scopic observations  upon  fatty  degeneration  of  tissues,  and 
on  the  other  from  metabolic  investigations.23 

In  the  years  from  1862  to  1871  Carl  Voit  in  association 

>9  Dakin,  Jour,  of  Physiol.,  32,  199,  1905. 

-°A.  S.  Loevenhart  (Johns  Hopkins  Univ.),  Jour,  of  Biol.  Chem.,  2,  391, 
415,  1907. 

21  E.  Hoyer,  Zeitschr.  f.  physiol.  Chemie,  50,  414,  1907. 

22  Cf.  A.  Welter,  Zeitschr.  f.  angew.  Chem.,  24,  385,  1911,  cited  in  Chem. 
Centralbl.,  1911',  1258. 

23  Literature  upon  Pat  Formation  from  Protein  in  Metabolism :  G.  Rosen- 
feld,  Ergebn.  d.  Physiol.,  1,  655-699,  1902;  R.  Tigerstedt,  Nagel's  Handb.  d. 
Physiol.,  1,  511-512,  1905;  A.  Magnus-Levy  and  L.  F.  Meyer,  Handb.  d. 
Biochem.,  //,  451-453,  1909. 


FORMATION  OF  FAT  FROM  PROTEIN  407 

with  Pettenkofer  in  a  series  of  extensive  studies  developed 
the  theory  that  protein  is  the  principal  source  of  fat  in  the 
living  body.     For  decades  metabolic  physiology  remained 
under  the  domination  of  this  doctrine,  supported  as  it  was 
by  the  great  authority  of  its  founders,  until  it  was  over- 
thrown by  the  ponderous  opposition  of  E.  Pflüger.    ' '  These 
celebrated  experiments  of  Voit  and  Pettenkofer,"  wrote 
Pflüger  at  the  beginning  of  the  nineties, ' '  prove  nothing  for 
the  formation  of  fat  from  protein.    For  the  computations  of 
these  investigators,  as  here  involved,  are  really  the  result  of 
a  mistaken  assumption  as  to  the  elementary  composition  of 
lean  meat,  which  Voit  adopted,  not  after  analysis,  but  from 
his  personal  judgment,  in  contravention  of  analyses  of  other 
investigators  generally  regarded  as  reliable,  and  in  fact  con- 
trary to  the  results  of  his  own  analyses.     It  is  on  such  a 
foundation  that  the  modern  superstructure  of  metabolism 
rests  for  the  majority  of  physiologists. ' '  In  answer  to  these 
ideas  the  Voit  school  set  about  energetically  to  defend  itself; 
and  in  particular  E.  Voit,  M.  Cremer  and  M.  Grruber  brought 
forward  new  arguments  for  the  retention  of  a  carbon  residium 
after  meat  consumption  which  did  not  seem  covered  by  the 
carbohydrate  in  the  food,  and  which,  therefore,  was  held  to 
indicate  a  formation  of  fat  from  protein.    Pflüger  invariably 
returned  to  the  fray  with  new  objections,  of  the  correctness 
of  which  different  opinions  might  be,  and  in  fact  were  held. 
To-day  the  whole  question  has  shifted;  since,  as  has  been 
stated,  we  must  necessarily  accept  the  formation  of  sugar 
from  protein  as  a  settled  fact,  and  cannot  possibly  doubt 
that  fat  is  formed  from  sugar.      The  logical  conclusion, 
therefore,  follows  that  it  must  be  granted  that  in  the  living 
body  fat  may  be  formed  from  protein.    It  is  another  ques- 
tion,  of  course,  whether  under  practical  conditions  this 
possibility  becomes  an  actuality.    When  very  large  amounts 
of  protein  are  fed  one  would  probably  always  contemplate 
such  a  result.     Magnus-Levy,  as  well-informed  in  the  funda- 
mental points  as  he  is  an  objective  observer  in  the  subject  of 


408  FORMATION  OF  FAT  FROM  PROTEIN 

metabolism,  believes  that  really  the  formation  of  fat  from 
protein  does  not  occur  to  any  important  amount,  although 
the  possibility  of  such  process  must  be  maintained.  Nor  is  it 
absolutely  essential  that  the  route  should  be  through  a  fully 
formed  sugar;  for  if  we  may  presume  that  groups  of  six 
carbon  atoms,  combined  from  the  "building  stones"  of  the 
protein  molecule,  unite  to  the  formation  of  the  sugar  mole- 
cule, we  have  as  much  right  to  fancy  that  eight  or  nine  such 
groups,  if  need  be,  can  enter  into  the  construction  of  the  long 
fatty  acid  chains.  When,  however,  would  this  be  needed? 
"When  carbohydrates  and  fat  are  available  in  metabolism 
there  is  no  occasion  for  further  production  from  protein. 
Whenever,  in  case  of  deficiency  of  carbohydrate,  important 
amounts  of  sugar  are  formed  from  protein,  it  seems  to  be 
required  for  the  immediate  needs  of  the  body,  unless,  as  in 
diabetics,  it  is  excreted.  As  we  cannot  recognize  in  animal 
experiments  that  in  case  of  exclusive  protein  diet  any  exten- 
sive formation  of  fat  takes  place,  so  there  is  no  reason  for 
holding  that  the  process  plays  any  important  part  under 
natural  conditions  of  life  in  the  carnivorous  individual. ' ' 24 
On  the  contrary,  only  recently  E.  A.  Bogdanow  has  con- 
cluded from  his  studies  on  the  fattening  of  pigs  that  fat  for- 
mation from  protein  is  at  least  probable.25 

Tangl  and  Farkas  26  have  found  an  increase  in  fat  con- 
tent of  trout-eggs  in  the  course  of  development  which  was 
held  to  be  due  to  transformation  of  protein  into  fat  because 
the  undeveloped  egg  does  not  contain  any  important  supply 
of  either  glycogen  or  sugar ;  although  the  possibility  of  gly- 
coproteid  with  its  carbohydrate  group  in  combination  in  pro- 
tein, should  be  considered. 

It  is  the  same  old  story :  the  great  conflict  over  the  for- 
mation of  fat  from  protein  in  metabolism  has,  if  the  expres- 

M  A.  Magnus-Levy  and  L.  F.  Meyer,  1.  c,  p.  453. 

ME.  A.  Bogdanow  (Moscow,  1909),  cited  from  the  Russian  in  Jahresber. 
f.  Tierchem.,  89,  585,  1909. 

*  F.  Tangl  and  Farkas  (Budapesth),  Pfliiger's  Arch.,  10  >h  624,  1904. 


FAT  PHANEROSIS  IN  AUTOLYSIS  409 

sion  be  allowed,  stalled  in  the  sand — more  exactly  stated,  has 
found  its  own  natural  solution.  It  would  be  difficult  to  fore- 
go the  opportunity  to  add  here  a  moral  reflection  that,  al- 
though in  the  determination  of  private  differences  it  is  not 
always  possible  to  get  along  without  disturbances  of  temper, 
it  should  always  be  a  rule  to  deal  with  differences  of  scientific 
opinion  with  equanimity  and  without  feeling ;  in  confidence 
that,  with  the  progress  of  knowledge,  that  which  is  right  is 
bound  to  win  recognition  entirely  of  its  own  strength.  The 
writer  might,  however,  in  an  objective  manner  equally  add 
that  here,  as  well  as  elsewhere,  it  is  much  easier  and  more 
convenient  to  give  good  advice  to  others  than  to  practice  it 
personally. 

Thus  far,  we  have,  however,  been  dealing  with  but  one 
side  of  the  problem  of  formation  of  fat  from  protein,  that 
which  is  manifest  to  us  in  metabolic  experimentation.  The 
question,  however,  has  many  other  sides  for  consideration 
in  turn.  A  historical  development  of  the  question  from  the 
beginning  may  be  dispensed  with,  the  writer  contenting  him- 
self with  an  explanation  of  its  present  status. 

Fat  Phanerosis  in  Autolysis. — Probably  it  will  be  best 
to  consider  first  the  simpler  phenomena  and  then  pass  on  to 
the  more  complicated,  taking  up  first  the  subject  of  "fatty 
degeneration"  of  tissues  occurring  in  extracorporeal  auto- 
lysis. Here  there  is  at  no  time  a  possibility  of  the  fat  being 
introduced  by  the  blood  stream  and  deposited  as  an  infiltra- 
tion. Since,  as  has  been  noted  by  numerous  authors,27  in 
tissue  autolysis  there  are  histological  pictures  reminding  one 
fully  of  fatty  degeneration,  two  possibilities  are  here  pre- 
sented :  either  fat  is  being  formed  de  novo  through  f ermen- 
tative  changes  or  else  fat  which  was  previously  present,  but 
which  was  not  directly  visible  and  was  not  demonstrable  by 
the  usual  methods  of  staining,  is  being  made  appreciable  to 
us  by  the  autolytic  process.     This  last  has  recently  been  ex- 

27  Cf .  the  older  Literature  upon  Fatty  Degeneration  in  Autolysis :  G.  Rosen- 
feld,  Ergebn.  d.  Physiol.,  2,  89-94,  1903. 


410  FORMATION  OF  FAT  FROM  PROTEIN 

pressed  by  the  very  appropriate  term  "fat  phanerosis."  A 
large  number  of  careful  investigations,  especially  those  (con- 
ducted under  direction  of  P.  Hofmeister)  of  F.  Kraus  2S 
and  of  F.  Siegert,29  as  well  as  those  of  Gr.  Rosenfeld,30  and 
A.  Slosse 31  and  a  number  from  the  Medical-chemical  Insti- 
tute in  Tokio,32  have  shown  that  the  formation  de  novo  of 
the  higher  fatty  acids  is  impossible  in  autolysis  without  bac- 
terial contamination.  A  few  statements  adverse33  to  this 
view,  in  the  author's  opinion,  prove  absolutely  nothing,  as 
the  technique  involved  is  by  no  means  above  objection.  It  is 
especially  unfair  to  account,  for  such  purpose,  only  the  bare 
ethereal  extract  as  fat;  the  tissues  must  be  completely 
broken  down  by  an  intense  saponifying  process  (as  in  the 
methods  of  Liebermann  and  of  Kumagawa  and  Suto)  34  and 
their  higher  fatty  acids,  poorly  soluble  in  water,  estimated 
as  fat  as  well.  There  is  not  the  least  contribution  to  the 
solution  of  the  situation  in  the  attitude  of  Waldvogel,  who 
instead  of  simplifying  the  problem  by  reverting  to  the  iso- 
lated higher  fatty  acids  introduced  into  the  question 
"hepatic  protagon"  and  "jecorin"  (more  than  problematic 
in  its  chemical  individuality),  and  tried  to  make  the  latter 
an  intermediate  product  between  protein  and  fat,  for  which 
assumption  there  was  not  even  the  shadow  of  proof. 

From  the  fact  that  in  prevailing  opinions,  as  will  be  dis- 
cussed later,  we  are,  in  the  production  of  a  fatty  liver  from 

28  F.  Kraus  (F.  Hofmeister's  Lab.,  Prague),  Arch.  f.  exper.  Pathol.,  22, 
174,  1897. 

29  F.  Siegert  (F.  Hofmeister's  Lab.,  Strassburg),  Hofmeister's  Beiträge,  1, 
114,  1902. 

?0G.  Rosenfeld,  Ergebn.  d.  Physiol.,  2,  90,  1903. 

£1  A.  Slosse  (Brussels),  Arch,  internat.  de  Physiol.,  1,  384,  cited  in  Biochem. 
Centralbl.,  3,  No.  711,  1904. 

S2Kohshi  Ota,  Biochem.  Zeitschr.,  29,  1,  1910;  N.  Shibata,  ibid.,  31,  321, 
1911. 

"Kotsowski,  Waldvogel,  Leathes;  cf.  the  criticism  of  J.  Meinertz  (Thier- 
felder's  Lab.),  Zeitschr.  f.  physiol.  Chem.,  U,  371,  1905. 

84  In  reference  to  the  Literature  upon  the  more  modern  Methods  of  Fat 
Analysis:  Cf.  the  articles  by  Röhmann,  Rosenfeld,  and  by  Kumagawa  and 
Suto,  in  Abderhalden^  Handb.  d.  biochem.  Arbeitsmethoden,  5',  477-488,  1911. 


FAT  PHANEROSIS  IN  AUTOLYSIS  411 

phosphorus  poisoning,  dealing  with  an  immigration  of  fat 
from  the  blood  stream,  that  is,  with  a  fatty  infiltration,  one 
must  necessarily  be  intensely  interested  in  the  statement  of 
Mavrakis 35  that  there  may  be  found  the  well-known  his- 
tological appearance  of  fatty  degeneration  in  specimens 
when  an  aqueous  suspension  of  yellow  phosphorus  has  been 
injected  into  a  branch  of  the  portal  vein  of  a  liver  which  has 
been  excluded  from  the  circulation  and  then  left  otherwise 
unmolested.  Under  the  author's  direction  his  student, 
P.  Saxl,36  has  repeated  this  experiment.  He  was  able  to 
fully  convince  himself  that  under  the  experimental  condi- 
tions named  tissue  changes  may  be  produced  which  are 
histologically  entirely  comparable  to  the  picture  of  fatty 
degeneration.  Exact  analyses,  however,  indicated  that  even 
in  this  case  there  is  no  actual  new  formation  of  fat  by  con- 
version of  the  protein  of  the  cellular  protoplasm,  but  that 
because  of  the  increased  tissue  autolysis  there  is  a  his- 
tological manifestation  of  fat  previously  present  but  in- 
visible. Here,  too,  should  be  mentioned  the  experiments  of 
Ernst  Weinland,  in  the  course  of  which  he  believed  he  found 
evidence  of  an  autolytic  new  formation  of  higher  fatty  acids 
"absolutely  in  minute  but  relatively  in  large  amount"  in  the 
expressed  juice  of  the  larvas  of  certain  flies  (calliphora) ; 
which  new  formation,  following  the  Voit  traditions,  he  inter- 
preted as  a  formation  of  fat  from  protein.  As  a  matter  of 
fact,  however,  with  general  recognition  of  the  care  involved 
in  these  studies,  it  seems  probable  to  the  author  that  only  the 
more  recent  experiments  of  Weinland 37  have  been  conducted 
with  a  reliable  method  of  estimating  fatty  acids,  and  that  his 
absolute  results  are  quite  too  small  and  variable  to  permit 
one  to  recognize  them  as  proving  the  position  (fat  disintegra- 

35  C.  Mavrakis  (Athens) ,  Arch.  f.  Anat.  u.  Physiol.,  190 k,  94. 

S6P.  Saxl  (under  direction  of  O.  v.  Fürth),  Hofmeister  's  Beitr.,  10, 
447,  1907;  L.  Hess  and  P.  Saxl  (v.  Noorden's  Clinic,  Vienna),  Virchow's  Arch., 
202,  148,  1910;   cf,  also  A.  Krontowski  (Kiev),  Zeitschr.  f.  Biol.,  54,  479,  1908. 

37  E.  Weinland  (Munich),  Zeitschr.  f.  Biol.,  52,  1909;  cf.  also  Biol.  Cen- 
tralbl.,  29,  565,  1909. 


412  FORMATION  OF  FAT  FROM  PROTEIN 

tion  also  takes  place  in  the  larval  pulp,  and  there  is  even  said 
to  be  a  periodicity  between  increase  and  loss  of  fat  in  the 
ground-up  maggots).  We  may  conclude,  then,  that  there  is 
no  proof  of  the  new  formation  of  higher  fatty  acids  from 
protein  in  autolysis,  that  in  fact  this  is  highly  improbable, 
and  that  all  of  the  microscopic  observations  which  apply  here 
may  be  interpreted  very  satisfactorily  as  instances  of  "fat 
phanerosis." 

Nature  of  Fat  Phanerosis. — Are  we  actually  in  position 
to  offer  a  precise  chemical  interpretation  of  the  phenomenon 
of  fat  phanerosis?  In  the  first  place,  are  we  dealing  here 
with  a  process  of  a  chemical  or  of  a  physical  nature?  In 
the  writer's  opinion  it  partakes  of  both.  It  is  essential  that 
we  conceive  of  the  fat  substances  in  the  cells  of  the  tissue  for 
the  most  part,  not  as  neutral  fat,  but  as  made  up  of  a  variety 
of  Phosphatids.  We  are,  moreover,  undoubtedly  fully  justi- 
fied in  supposing,  as  Friedrich  v.  Müller  suggested  years 
ago,  that  changes  which  involve  these  Phosphatids  in  the 
course  of  autolysis  are  connected  with  fat  phanerosis.  Yet 
even  without  such  an  assumption  it  is  possible  to  fancy  that 
the  cells,  as  the  result  of  autolytic  processes,  have  lost  their 
ability  of  maintaining  fat  in  a  state  of  solution,38  as  perhaps 
in  connection  with  cellular  swelling,  coagulation  and  acid 
changes.  Then,  too,  we  may  think  that  possibly  true  chem- 
ical combinations  between  fatty  acids  and  proteid  bodies 
{"lipoproteids")  exist,  which  may  undergo  cleavage  in  the 
autolytic  process. 

In  this  aspect  it  is  of  interest  to  recall  that  amido-com- 
binations  between  high  fatty  acids  and  aminoacids  (as  those 
synthetically  reconstructed  in  the  first  place  by  Bondi 39  and 
again  by  Abderhalden,40  and  their  co-workers)  in  contrast  to 
free  fatty  acids  are  not  soluble  in  ether,  do  not  take  up  the 

38  Cf.  V.  Rubow  (Copenhagen),  Arch.  f.  exper.  Pathol.,  52,  174,  1905. 

39  S.  Bondi,  in  association  with  T.  Frank!  and  F.  Eissler  ( J.  Mauthner's 
Lab.,  Vienna),  Biochem.  Zeitschr.,  17,  1909,  and  23,  1910. 

40  E.  Abderhalden  and  C.  Funk,  Zeitschr.  f.  physiol.  Chem.,  65,  61,  1910. 


HOFFMANN'S  EXPERIMENT  413 

fat-staining  reagents,  and  are  split  into  their  components  by 
the  ferment  action  of  autolyzing  tissue  (but  not  by  trypsin). 

Having  in  some  degree  come  to  an  appreciation  of  these 
points,  a  further  step  may  be  taken  and  attention  given  to 
other  examples  of  the  supposed  formation  of  fat  from 
protein. 

Formation  of  Higher  Fatty  Acids  by  Microorganisms. — 
We  at  once  encounter  here  the  fact,  of  importance  to  appre- 
ciation of  the  general  problem,  that  we  must  acknowledge 
without  question  the  power  of  forming  fat  from  protein  as 
belonging  to  the  lower  vegetable  organisms  (a  power  which, 
as  far  as  the  animal  organism  is  concerned,  if  not  absolutely 
contested,  can  be  recognized  only  conditionally  and  with 
much  reservation  with  the  preformation  of  sugar  from  pro- 
tein in  mind).  A  long  time  ago  Emmerling  concluded  that 
higher  fatty  acids  are  produced  in  culture  of  staphylococcus 
pyogenes  aureus  on  egg  albumin.  The  experiments  of  several 
American  authors  (Beebe  and  Buxton)  41  seem  particularly 
significant  in  this  connection.  They  have  shown  that  if 
bacillus  pyocyaneus  be  cultivated  on  media  free  from  sugar 
and  from  fat,  such  quantities  of  fatty  substances  are  formed 
that  they  become  evident  on  the  culture  surface  in  the  form 
of  microscopic  needle-shaped  crystals. 

Hoffmann's  Experiment  with  Fly-maggots. — The  ability 
of  microorganisms  to  construct  fat  out  of  protein  explains 
other  points ;  particularly  the  famous  maggot  experiment 
made  by  Franz  Hoffmann  in  the  early  seventies.  This  in- 
vestigator determined  the  fat-content  of  a  portion  of  a  num- 
ber of  fly-eggs  and  then  allowed  the  remainder  to  develop 
upon  defibrinated  blood.  It  was  proved  at  the  close  of  the 
experiment  that  the  fat-content  of  the  larvae  exceeded  by 
tenfold  the  sum  of  the  egg-fat  and  of  the  fat  in  the  blood. 
Long  ago  Pflüger 's  acumen  suggested  the  apparently  perti- 
nent interpretation  for  this  experiment,  which  was  later 

41  S.  P.  Beebe  and  B.  H.  Buxton  (Cornell  Univ.,  New  York),  Amer.  Jour,  of 
Physiol.,  12,  466,  1905. 


414  FORMATION  OF  FAT  FROM  PROTEIN 

repeated  with  unsatisfactory  result  by  Otto  Frank,  that  the 
enormous  numbers  of  bacteria  present  in  the  cultures  were 
to  be  suspected  of  bringing  about  the  trick  of  building  up 
fatty  acids  from  protein. 

Adipocere. — Another  puzzling  natural  phenomenon, 
which  is  constantly  used  as  an  example  of  the  formation  of 
fat  from  protein  in  the  animal  economy  is  that  of  the  produc- 
tion of  cadaveric  wax*2  As  is  well  known  adipocere  is 
formed  when  corpses  or  parts  of  corpses  are  buried  in  moist 
places  or  are  kept  in  contact  with  water,  the  muscles  and 
soft  parts  being  replaced  by  a  mass  made  up  of  a  mixture  of 
free  fatty  acids  along  with  palmitates  and  stearates  of  mag- 
nesium, calcium  and  ammonium.  There  was  formerly  a 
common  disposition  to  regard  the  process  as  one  of  a  direct 
production  of  fat  from  protein.  "We  are  at  present  inclined 
to  assume  that  we  are  dealing  only  with  the  fatty  acids  which 
were  previously  present  in  the  structures ;  that  through  the 
influence  of  lipases  and  putrefying  bacteria  the  neutral  fats 
are  split  into  their  components,  the  fatty  acids  rendered 
soluble  by  combining  with  the  ammonia  produced  by  putre- 
faction, and  the  soap  solution  then  permeating  and  percolat- 
ing through  the  soft  parts ;  that  thereafter  by  replacement 
of  the  ammonia  of  the  soaps  by  calcium  and  magnesium  salts 
there  results  the  formation  of  relatively  insoluble  precipi- 
tates. There  are,  however,  statements  to  the  effect  that  the 
total  quantity  of  fatty  acids  in  the  formation  of  adipocere 
undergoes  a  definite  increase.  In  view  of  the  gross  tech- 
nical errors  involved  in  the  older  analyses  it  is  very  difficult 
to  properly  evaluate  this  contention.  It  would  appear,  how- 
ever, that  even  if  an  actual  formation  de  novo  of  the 
higher  fatty  acids  be  recognized  when  adipocere  is  formed, 
the  agency  of  bacteria  may  be  looked  upon  as  largely 
explanatory. 

42  Literature  upon  Adipocere:  G.  Rosenfeld,  Ergebn.  d.  Physiol.,  V ,  659- 
664,  1902;  H.  G.  Wells,  Chemical  Pathology,  1st  ed.,  342-343,  1907;  cf.  therein 
the  work  of  Kratter,  Ermann,  Zillner,  E.  Voit,  Lehmann,  Salkowski ;  cf.  also 
C.  Ipsen  (Innsbruck),  Ber.  der  Univ.,  1909,  cited  in  Jahresber.  f.  Tierchem., 
1910,  891. 


PHOSPHORUS  POISONING  415 

Formation  of  Fat  in  the  Ripening  of  Cheese. — Precisely 
the  same  is  true  in  case  of  the  old  problem  of  the  formation 
of  fat  in  the  ripening  of  cheese.43  It  may  be  accepted  as 
proved  that  there  actually  is  an  increase  in  the  ethereal  ex- 
tract when  cheese  is  ripened.  Yet  recently  M.  Nierenstein 44 
has  called  attention  to  the  point  that  this  increase  need  not 
necessarily  be  referred  to  an  increase  in  fat  alone,  as  in  the 
ethereal  extract  in  addition  to  fat  and  cholesterol  there  are 
also  present  putrescine,  cadaverine,  etc.  But  where  actual 
new  formation  of  higher  fatty  acids  is  taking  place  (and 
there  is  scarcely  basis  for  doubting  this)  there  is  reason 
to  at  least  suspect  it  to  be  due  to  the  activity  of  micro- 
organisms. 

Accumulation  of  Fat  in  the  Liver  in  Phosphorus  Poison- 
ing.— Having  progressed  with  reasonable  assurance  thus  far, 
we  may  venture  with  confidence  upon  a  question  which  in  a 
certain  measure  is  the  central  point  of  the  whole  problem, 
namely,  that  of  intravital  fatty  change  of  the  tissues.45 

"Fatty  degeneration  of  the  liver"  in  phosphorus  poison- 
ing has  been  held  up  as  a  classical  example  of  such  change  for 
the  longest  time;  for  this  reason  the  process  should  be  con- 
sidered next  in  turn,  the  more  so  because  its  essential  nature 
seems  at  present  to  be  satisfactorily  understood.  While  the 
older  pathologists  permitted  themselves  to  be  so  much  im- 
pressed by  the  microscopic  picture  of  the  fatty  degenerated 
liver  as  to  have  no  doubt  whatever  as  to  the  occurrence  here 
of  a  transformation  of  protein  into  fat,  we  know  to-day  that 
the  bulk  of  the  fat  in  a  phosphorus  liver  has  really  come  as  a 
fatty  infiltration  into  the  organ.  This  has  been  proved  with 
thoroughly  satisfactory  exactness. 

In  the  first  place,  contrary  to  the  older  statements  to  the 

43  Literature  upon  Fat  Formation  in  the  Ripening  of  Cheese :  G.  Rosen- 
feld,  Ergebn.  d.  Physiol.,  V ,  663-664,  1902. 

44  M.  Nierenstein  (Bristol),  Proc.  Roy.  Soc,  Series  B,  83,  301,  1911,  cited  in 
Centralbl.  f.  d.  ges.  Biol.,  1911,  No.  2087. 

45  Literature  upon  Vital  Fatty  Degeneration  of  Tissues :  G.  Rosenfeld, 
Ergebn.  d.  Physiol.,  2,  64-86,  1903;  R.  Tigerstedt,  Nagel's  Handb.  d.  Physiol., 
1,  510-511,  1905. 


416  FORMATION  OF  FAT  FROM  PROTEIN 

opposite,46  complete  proof  has  been  furnished  by  a  series  of 
studies  47  showing  that  the  total  amount  of  fat  in  animals 
poisoned  by  phosphorus  does  not  undergo  any  increase; 
there  is  merely  a  change  in  the  fat  distribution,  in  conse- 
quence of  which  there  is  more  fat  accumulated  in  a  number 
of  tissues,  above  all  in  the  liver. 

Besides,  this  has  been  very  strikingly  confirmed  by  the 
recognition  that  the  fat  of  the  phosphorus  liver  corresponds 
in  its  composition  with  depot-fat,  and  that  if  the  fat  storage- 
sites  be  filled  with  fat  of  a  type  foreign  to  the  body  and  phos- 
phorus poisoning  is  then  induced,  this  foreign  form  of  fat 
will  accumulate  in  the  liver.  This  was  shown  first  by  Lebe- 
deff,  employing  linseed  oil,  then  by  G.  Rosenfeld,  who  used 
mutton-fat  and  cocoa-butter.  Similar  experiments  carried 
out  with  iodized  fat  by  Gideon  Wells  48  gave  an  uncertain 
result;  while  the  same  experiment  by  Schwalbe49  resulted 
positively. 

Finally  G.  Rosenfeld,  undertook  another  crucial  experi- 
ment, and  showed  that  the  fatty  change  does  not  occur  in 
phosphorus  poisoning  if  animals  which  are  very  poor  in  fat 
be  used.  The  outcome  of  this  experiment  proves  how  fatty 
change  comes  to  involve  the  liver  in  phosphorus  poisoning: 
were  we  to  assume  that  it  is  due  to  a  breaking  down  of  protein 
into  fat,  then  necessarily  phosphorus  should  invariably  pro- 
duce a  fatty  liver,  because  the  assumed  mother  substance  of 
the  fat,  protein,  is  always  present.  If  the  change,  however, 
is  the  result  of  a  passage  of  the  depot-fat  into  the  liver,  the 
condition  must  fail  to  appear  if  no  depot-fat  is  available  for 
immigration.50  Actually,  too,  under  these  circumstances,  it 
does  not  appear. 

**  Leo,  Polimanti. 

"Athanasiu  (E.  Pfliiger's  Lab.),  Taylor,  1899;  F.  Kraus  and  Sommer, 
1902;  J.  Barro,  Jahresber.  f.  Tierchem.,  31,  75,  1902;  Boruttau,  Arch,  de  Fisiol., 
2,  26,  1904;    Shibatu  Negamachi,  Biochem.  Zeitschr.,  «37,  345. 

48  H.  G.  Wells  (Chicago),  Zeitschr.  f.  physiol.  Chem.,  Jf5,  412,  1905. 

49  Schwalbe  (Heidelberg),  Verh.  d.  deutsch,  pathol.  Gesellsch.,  Kassel, 
1903,  71. 

80  G.  Rosenfeld,  Ergebn.  d.  Physiol.,  2',  68,  1903. 


ROSENFELD'S  THEORY  417 

Fatty  Infiltration  in  Other  Pathological  Conditions. — 
Whatever  is  true  of  the  origin  of  the  fatty  liver  in  phos- 
phorus poisoning  seems,  from  all  we  know  thereof,  to  be  also 
applicable  in  case  of  the  fatty  livers  which  follow  poisoning 
from  arsenic,  antimony,  chloroform,  alcohol  and  many  other 
poisons.  There  are  many  other  pathological  conditions  in 
which  at  times  a  typical  fatty  liver  is  met,  as  for  example, 
starvation,  phloridzin  diabetes  and  pancreatic  diabetes  51 
and  overheating.  (It  was  customary  for  a  long  time  in 
France  in  producing  fatty  livers  in  geese  to  confine  them  in 
small,  warm  coops.)  We  have  no  substantial  reason  for 
doubting  that  in  such  instances,  as  well  as  in  the  so-called 
"liver  of  pregnancy,"52  we  are  dealing  with  the  phenomena 
of  typical  fatty  infiltration. 

Rosenfeld's  Theory. — Are  we  able  to  offer  any  explana- 
tion for  the  fact  that  the  same  process,  fatty  infiltration  of 
the  liver,  is  common  to  pathological  conditions  of  the  most 
diverse  type?  G.  Rosenfeld,  basing  his  views  upon  the  fact 
that  in  the  different  fatty  livers  due  to  intoxications  the 
organ  is  generally  devoid  of  glycogen  and  that,  for  example, 
in  phloridzin  intoxication  the  production  of  a  fatty  liver  may 
be  inhibited  by  free  administration  of  sugar,  meat 53  and 
other  substances  which  go  to  form  glycogen,  has  formulated 
the  following  line  of  thought :  "If  cells  are  brought  under 
the  influence  of  any  sort  of  noxious  agent  .  .  .  they  in- 
crease their  resistive  power  by  oxidation  of  every  bit  of 
carbohydrate  of  which  they  may  be  possessed  (for  which  rea- 
son the  liver  of  the  animal  with  phosphorus  poisoning  is  free 
of  glycogen).  ...  If  there  is  no  reserve  material  or  an 
amount  insufficient  to  protect  the  cellular  protein,  the  cells 
take  recourse  to  their  last  adjuvant;  they  attempt  to  re- 
store their  supplies  for  production  of  resistive  power  by 

51  H.  Lattes,  Arch.  Scienze  med.  Torino,  33,  cited  in  Jahresber.  f .  Tierchem., 
40,  816,  1910. 

62  J.  Hofbauer  (Königsberg),  Arch.  f.  Gynäkol,  93,  405,  1909. 

53  G.  Rosenfeld  (Breslau),  Berliner  klin,  Wochenschr.,  41,  1268,  1910. 

27 


418  FORMATION  OF  FAT  FROM  PROTEIN 

taking  up  an  increased  amount  of  fat.  Res  redit  ad  triarios: 
the  last  reserves  enter  the  fray  if  the  legionaries  are  de- 
stroyed. If  the  cell  then  succeeds  in  mastering  the  poison, 
the  victory  is  through  the  aid  of  a  fatty  regeneration ;  if  even 
this  be  of  no  service,  the  cell  dies  the  death  of  a  hero ;  in  spite 
of  the  fatty  infiltration  degeneration  ensues. ' ' 54 

Association  of  Fat  Phanerosis  in  the  Phenomena  of 
Fatty  Degeneration. — Probably,  however,  it  is  not  correct 
to  end  the  matter  by  attributing  solely  to  fatty  infiltration 
all  of  the  appearances  which  the  older  pathologists  recog- 
under  the  name  ''fatty  degeneration."  To  the  author's 
mind  it  is  entirely  logical  to  assume  as  well  a  superimposi- 
tion  of  the  process  of  fat  phanerosis.  We  have  had  under 
discussion  the  fact  that  when  phosphorus  is  injected  into  the 
portal  vein  the  picture  of  a  fatty  degeneration  may  be  pro- 
duced even  in  a  liver  removed  from  the  body.  Besides  in  case 
of  the  isolated,  artificially  perfused  hearts  of  warm-blooded 
animals  it  has  been  shown  that  the  same  noxious  factors  (as 
incomplete  nutrition  and  poisons)  which  cause  fatty  de- 
generation in  the  living  body,  give  rise  to  "fatty  change" 
also  of  the  isolated  heart,  in  which  there  can  be  no  sus- 
picion of  the  entrance  of  fat  from  any  of  the  fat  depots.55 
Di  Christina,  for  example,  ascribed  to  phosporus  two  entirely 
distinct  influences,  one  a  necrosing,  the  other  a  steatogenous 
action  (the  latter  in  the  sense  of  a  mobilization  of  fat  in  the 
depots).50  We  have,  too,  every  reason  for  assuming  that  an 
intoxication,  such  as  phosphorus  poisoning,  does  not  leave 
the  protein  material  of  the  liver  undisturbed ;  according  to  a 
study  made  in  KossePs  laboratory  57  catabolism  of  the  pro- 
tein molecule  is  likely  to  result  in  a  spliting  off  of  compounds 
rich  in  bases  with  a  residue  of  material  poor  in  bases  and 
nitrogen.     That  such  a  process  of  disintegration  cannot  be 

64  G.  Eosenfeld,  1.  c,  p.  84. 

68  A.  Cesaris-Demel  (Pisa),  Arch.  ital.  de  Biol.,  51,  197,  1908. 
M  Di  Christina,  Virchow's  Arch.,  181,  509,  1905. 

"A.  J.  Wakeman  (A.  Kossel's  Lab.,  Heidelberg),  Zeitschr.  f.  physiol. 
Chem.,  M,  335,  1905. 


FATTY  CHANGE  OF  THE  KIDNEY  419 

thought  of  as  unattended  by  serious  change  of  the  physical 
and  chemical  characters  of  the  hepatic  proteins,  goes  with- 
out saying.  The  view  indicated  by  Mansfield  therefore  is 
decidedly  plausible,  this  writer  from  his  observations  upon 
fat  combination  (v.  supra,  p.  370)  believing  it  quite  char- 
acteristic of  phosphorus  poisoning  that  there  should  exist  a 
loss  in  the  power  of  the  haemic  and  tissue  proteins  to  fix  fat.58 
The  author  would  readily  believe  that  the  assumption  of 
such  a  change  in  the  ability  to  fix  fat  would  make  it  possible 
to  regard  the  features  of  fat  phanerosis  and  those  of  fat 
migration  from  a  common  point  of  view.  The  fundamental 
cause  which  destroys  the  union  between  the  fats  and  the  cells 
of  the  fat  depots,  and  brings  about  mobilization  of  the  latter 
as  well  as  fatty  infiltration  of  the  liver,  may  very  well  be  the 
same  as  that  which  breaks  up  the  bond  between  the  tissue- 
fat  and  the  tissue-cells,  and  which  in  this  way  induces  fat 
phanerosis  (that  is,  brings  into  view  fat  which  was  previ- 
ously invisible).  In  this  sense  we  may,  therefore,  perhaps 
look  upon  fatty  infiltration  and  fat  phanerosis  as  different 
phases  of  one  and  the  same  process. 

" Fatty  degeneration"  is  by  no  means  necessarily  con- 
fined to  the  liver,  but  may  involve  other  structures  as  well, 
as  the  cardiac  and  skeletal  musculature,  the  kidneys,  the 
lungs  and  the  epithelium  of  the  intestinal  tract.59 

Fatty  Change  of  the  Kidney. — A  few  remarks  at  this 
point  in  reference  to  fatty  change  of  the  kidneys  may  not  be 
inappropriate. 

Kosenfeld  and  several  other  investigators  had  concluded 
that  the  histological  observations  of  a  fatty  change  of  a 
kidney  could  not  be  regarded  as  having  any  real  reference  to 
the  actual  amount  of  fat  in  the  organ ;  that,  although  a  kid- 
ney may  appear  to  be  "fatty  degenerated,"  actually  its  fat 

68  G.  Mansfeld  ( in  collaboration  with  E.  Hamburger  and  F.  Verzär,  Phar- 
macolog.  Instit.,  Budapesth),  Pflüger's  Arch.,  129,  46,  1909. 

"J.  and  S.  Bondi  (v.  Noorden's  Clinic  and  R.  Paltauf's  Lab.,  V7ienna), 
Zeitschr.  f.  exper.  Pathol.,  6,  254,  1909. 


420  FORMATION  OF  FAT  FROM  PROTEIN 

content  may  be  decidedly  less  than  normally.60  In  opposi- 
tion to  this  idea  K.  Landsteiner  and  V.  Mucha 61  have  applied 
themselves  with  great  confidence.  As  a  matter  of  fact  if  the 
whole  kidney  is  not  analyzed  but  the  cortex  only  be  used 
(thus  excluding  the  fat  situated  about  the  renal  pelvis,  which 
has  nothing  whatever  to  do  with  pathological  processes), 
the  microscopic  determination  and  chemical  analysis  ap- 
parently agree  fairly  well.  Precise  analyses  conducted  in  E. 
Ludwig 's  laboratory  indicate  that  while  the  cortical  sub- 
stance of  the  kidney  may  normally  contain  at  most  as  much 
as  eleven  per  cent,  of  fat,  this  proportion  may  be  much  in- 
creased in  phosphorus  poisoning.  According  to  Landsteiner 
it  is  possible  to  distinguish  two  types  of  renal  fatty  change, 
the  one  a  true  fatty  infiltration  (as  in  the  diabetic  kidney), 
and  another  form  in  which  the  fat  deposit  is  associated  with 
distinct  cellular  destruction.  This  brings  into  prominence 
again  the  old  distinction  between  fatty  infiltration  and  fatty 
degeneration.  With  Gr.  Klemperer 62  one  may  believe  that  in 
the  latter  process  fat  phanerosis  may  also  be  granted  a  part. 
However,  sufficient  has  probably  been  said  to  indicate  that 
there  is  no  room  left  in  modern  thought  for  the  old  accepta- 
tion of  fatty  degeneration,  that  is,  that  it  involves  a  direct 
conversion  of  cellular  protein  into  fat. 

The  ability  of  the  kidney  to  construct  fat  from  its  com- 
ponents, it  may  be  remarked  in  passing,  has  been  proved  by 
Fischler  in  the  Heidelberg  Pathological  Institute.  He  per- 
fused a  living  kidney  with  blood  to  which  soap  and  glycerine 
were  added,  with  the  production  of  typical  pictures  of  fatty 
change  of  the  renal  epithelium.63 

eoG.  Rosenfeld,  1.  c,  pp.  78-81;  A.  Orgler  (Salkowski's  Lab.),  ibid.,  176, 
413,  1904;  E.  Kuznitsky  (Ribbert's  Lab.);  Baum  and  Rosenfeld  (Breslau), 
Berliner  klin.  Wochenschr.,  1909,  629. 

61 K.  Landsteiner  and  V.  Mucha  (Lab.  of  Weichselbaum  and  E.  Ludwig, 
Vienna),  Centralbl.  f.  allgem.  Pathol,  u.  pathol.  Anat.,  15,  18,  1904. 

62  G.  Klemperer  (Moabite  Hosp.,  Berlin),  Deutsche  med.  Wochenschr., 
1909,  89;  cf.  also  Löhlein  (Pathol.  Instit.,  Leipzig),  Virchow's  Arch.,  180,  1, 
1909. 

83  F.  Fischler  (Arnold's  Lab.,  Heidelberg),  Virchow's  Arch.,  Ill},  338,  1903. 


CHOLESTEROL-ESTER  STEATOSIS  421 

Cholesterol-ester  Steatosis. — The  problem  of  the  process 
of  fatty  change  would  be  incompletely  dealt  with  were  the 
author  not  to  mention  an  entirely  new  phase,  that  of  choles- 
terol-ester steatosis. 

As  previously  stated  (v.  Vol.  I  of  this  series,  p.  324,  Chem- 
istry of  the  Tissues)  the  esters  of  cholesterol  with  the  higher 
fatty  acids  are  of  interest  both  from  a  physiological  and  a 
pathological  point  of  view.  These  esters  have  been  demon- 
strated in  wool  fat,  in  epidermal  scales  by  Salkowski,64  in  the 
cutaneous  fat  by  Unna,65  and  in  the  blood  serum  by 
Hiirthle.66  It  has  been  shown  in  Eöhmann's  laboratory67 
that  in  the  acetic-ether  extract  of  the  liver,  along  with  free 
cholesterol,  a  certain  amount  of  cholesterol  esters  is  present, 
and  that  the  liver  also  contains  an  enzyme  capable  of  split- 
ting these  esters.  What  is  of  especial  interest  to  us,  how- 
ever, is  the  fact  that  a  crystalline,  doubly  refractive  sub- 
stance found  in  fatty  kidneys  has  been  determined  by  Pan- 
zer,65 in  Ernst  Ludwig  's  laboratory,  as  an  ester  of  cholesterol 
with  an  unsaturated  higher  fatty  acid.  This  discovery  has 
been  fully  confirmed  by  Windaus 69  by  his  digitonin  method 
of  determining  cholesterol ;  and  we  are  justified  in  assuming 
that  the  cholesterol  esters  actually  take  an  important  part  in 
the  formation  of  doubly  refractive  substances  in  fatty  tis- 
sues. The  pathologist  Aschoff  has  in  fact  seen  fit  to  regard 
cholesterol-ester  fatty  change  as  being  a  form  of  fat  metab- 
olism of  at  least  equal  importance  and  of  equivalent  origin 
to  glycerol-ester  fatty  change;  and  he  intrusted  his  pupil, 

ME.  Salkowski,  Arb.  a.  d.  Pathol.  Instit.,  Berlin,  A.  Hirschwald,  1906; 
Biochem.  Zeitschr.,  23,  362,  1910. 

co  Unna  and  Golodetz,  Biochem.  Zeitschr.,  20,  469,  1909. 

66  Hiirthle,  Zeitschr.  f.  physiol.  Chem.,  21,  331,  1895. 

«TK.  Kondo  (Röhmann's  Lab.,  Breslau),  Biochem.  Zeitschr.,  26,  238,  243, 
252,  427,  437,  1910. 

°T.  Panzer  (E.  Ludwig's  Lab.,  Vienna),  Zeitschr.  f.  physiol.  Chem.,  48, 
519,  1906;   54,239,  1907. 

08  A.  Windaus  (Freiburg),  Zeitschr.  f.  physiol.  Chem.,  65,  110,  1910;  cf. 
also  J.  Pringsheim,  Biochem.  Zeitschr.,  15,  52,  1907. 


422  FORMATION  OF  FAT  FROM  PROTEIN 

Kawamura,70  with  the  task  of  determining  by  means  of  a 
great  number  of  morphological  methods  (determination  of 
their  behavior  with  neutral  red,  nile-blue,  and  a  number  of 
other  staining  reagents,  their  refraction  in  glycerol,  etc.) 
whether  the  cholesterol-esters  can  be  definitely  distinguished 
from  the  glycerolesters  and  the  other  lipoids.  The  author 
contrasts  (unnecessarily  introducing  new  terms  for  previ- 
ously known  conditions)  steatosis  (fatty  infiltration)  with 
myelinosis  (fat  phanerosis),  and  divides  the  former  into 
glycerol-steatosis,  cholesterol-steatosis  and  lipoid  steatosis. 
It  is  very  clear  that  only  thorough  chemical  studies  in  close 
coordination  with  morphological  observations  could  possibly 
determine  the  value  of  such  classifications.  It  is,  however, 
quite  a  matter  for  congratulation  that  morphologists  are  also 
largely  being  brought  to  recognize  that  differentiation  by 
staining  methods  is  really  nothing  more  than  a  very  special 
form  of  chemical  or  physical-chemical  reaction,  and  that  it  is 
really  desirable  that  they  supplement  this  by  other  and  better 
defined  chemical  methods.  The  tremendous  enlargement  of 
the  sum  total  of  scientific  knowledge  is  constantly  leading  to 
the  rise  of  new  specializations  and  changes  of  limitations. 
Unfortunately  in  view  of  the  limited  receptive  power  of  the 
human  brain  this  cannot  be  avoided.  Yet  the  chemist,  idling 
between  his  tubes  and  his  jars,  and  ignoring  designedly  and 
stubbornly  everything  which  he  cannot  boil,  extract  and 
distill,  fits  just  as  sadly  in  the  field  of  modern  science  as  does 
the  morphologist,  to  whom  nothing  else  seems  worth  bother- 
ing about,  and  who  regards  nothing  as  important  as  his 
stained  sections.  Freer  vision  will  come  only  to  the  ap- 
pointed, to  him  for  whom  the  thickets  of  the  lowland  are  too 
confined  and  who  strives  upward  to  the  heights. 


70 R.  Kawamura,  Die  Cliolesterinesterverfettung  (Pathol.  Instit.,  Freiburg, 
i.  B.),  Jena,  G.  Fischer,  1911;  cf.  also  F.  M.  Hanes  (Columbia  Univ.,  New- 
York),  Johns  Hopkins  Hosp.  Bull.,  23,  77,  1912. 


ORIGIN  OF  MILK  FAT  423 

ORIGIN  OF  MILK  FAT 

As  the  final  subject  of  this  section  of  our  study  of  fat 
metabolism,  the  origin  of  the  fat  in  milk  may  be  presented 
for  consideration.71  In  bringing  this  subject  forward  in 
direct  connection  with  the  chapter  upon  the  processes  of 
fatty  change,  a  historical  rather  than  a  logical  relation  is 
being  followed. 

The  older  pathologists  looked  upon  the  origin  of  the  milk 
fat  as  an  example  of  supposed  conversion  of  protein  into  fat. 
Virchow  was  fully  convinced  that  both  the  fat  globules  and 
the  other  constituents  of  milk  arise  from  a  fatty  degeneration 
and  disintegration  of  the  cells  of  the  mammary  gland.  Then, 
later,  Haidenhain  modified  this  view  by  supposing  that  only 
that  part  of  the  gland  cell  next  to  the  lumen  sets  free  the  fat 
droplets  as  it  undergoes  disintegration.  C.  Voit,  in  connec- 
tion with  his  above  mentioned  doctrines,  advocated  the  idea 
that  protein  breaks  down  in  nursing  animals  in  such  manner 
that  its  nitrogen  is  excreted  as  urea  and  the  residue,  rich  in 
carbon,  is  secreted  as  fat  with  the  milk.  That  the  doctrine 
of  the  protein  origin  of  the  milk  fat  was  firmly  impressed  by 
the  weight  of  the  great  and  overpowering  authority  of  these 
men  upon  the  minds  of  physiologists  is,  of  course,  not  in  the 
least  remarkable ;  and  it  has  required  a  great  deal  of  labor  to 
evict  it.  Among  others,  the  noted  Heidelberg  pathologist, 
J.  Arnold  (to  whom  I  refer  as  one  of  my  teachers  with  special 
appreciation),  not  long  ago  undertook  to  reinvestigate  the 
subject  by  a  thorough  histological  study  of  the  mammary 
glands  of  women  and  female  animals.  He  came  to  the  con- 
clusion that,  contrary  to  the  assumption  of  Virchow,  even  the 
freest  secretion  of  milk  may  take  place  without  any  degener- 
ation of  the  cells  of  the  mammary  glands.  The  fat  appears 
in  the  interior  of  the  cells,  especially  in  the  basal  portion  of 
the  cytoplasm,  that  away  from  the  lumen  of  the  gland,  and 

"Literature  upon  Milk  Fat:  K.  Basch,  Ergebn.  d.  Physiol.,  2',  366-373, 
1903;  R.  W.  Raudnitz,  ibid.,  259-264,  1903;  A.  Magnus-Levy  and  L.  F.  Meyer, 
Hand.  d.  Biochem.,  .'/',  468,  1909;   L.  Kalabaukoff,  Biologie  mgdicale,  Jan.,  1909. 


424  ORIGIN  OF  MILK  FAT 

no  fat  is  to  be  seen  in  the  neighborhood  of  the  secretory  cells. 
Arnold  concludes  from  what  he  saw  and  with  the  prevailing 
status  of  metabolism  in  mind,  that  the  component  parts  of 
the  fat  are  brought  to  the  lactating  cells  from  without  in  a 
water-soluble  form,  and  that  the  fat  is  newly  constructed 
from  such  material  within  the  cellular  protoplasm  by  func- 
tionating vital  processes. 

What  then  do  we  really  know  of  the  origin  of  the  fat  in 
milk?  In  the  author's  opinion  it  is  necessary  to  recognize  a 
three-fold  origin.  It  arises  in  part  from  the  fats  of  the  food, 
in  part  from  those  of  the  fat  depots  of  the  body,  and  in  part, 
finally,  from  the  carbohydrates  which  are  undergoing  trans- 
formation in  the  economy  into  fat. 

Passage  of  the  Fat  of  the  Food  into  the  Milk. — As  far 
as  concerns  the  subject  of  passage  of  the  fat  of  the  food  into 
the  milk,  a  large  number  of  investigations  72  should  be  noted, 
in  which  studies  were  made  with  all  sorts  of  extraneous 
fats  (as  cottonseed  oil,  sun-flower  oil,  peanut  oil,  cocoa 
butter,  lindseed  oil,  oil  of  sesame,  almond  oil,  palm  oil, 
goose  fat,  mutton  suet,  iodized  and  brominized  fats)  and 
which  have  removed  all  doubt  from  the  subject.  The  ques- 
tion is  of  interest  not  only  from  a  general  scientific  view- 
point, but  has,  too,  a  very  decided  bearing  upon  medical 
practice.  The  general  composition  of  the  milk-fat  of  a 
nurse,  as  pointed  out  by  Engel 73  from  systematic  studies  in 
the  Dresden  Infants'  Home,  depends  upon  the  character  of 
the  fats  of  the  food  ingested.  The  importance  of  the  details 
of  diet  for  maintenance  of  health  of  the  normal  human  being 
has  unquestionably  been  very  greatly  exaggerated  by  the 
laity  generally ;  and  it  is  of  more  immediate  importance  to 

"Willy,  1889;  Stellwag,  1890;  Heinrich,  1891;  Klien,  1892;  Lehmann, 
1896;  Winternitz,  1897;  Rosenfeld,  1898;  Baumert  and  Falke,  1898;  Hen- 
riques  and  Hansen,  1899;  Caspari,  1899;  Engel,  1906;  Gogitidse,  Zeitschr.  f. 
Biol.,  45,  353,  1904;  Jt6,  403,  1905;  Jtl,  4:15,  1906;  W.  Caspari  and  H.  Win- 
ternitz, Zeitschr.  f.  Biol.,  49,  558,  1907;  cf.  Literature  in  K.  Basch,  1.  c,  and 
A.  Magnus-Levy  and  L.  F.  Meyer,  1.  c,  p.  468. 

73  Engel  (Schlossmann's  Clinic),  Arch.  f.  Kinderheilk.,  .',3,  194,  1906; 
Zeitschr.  f.  physiol.  Chem.,  U,  352,  1905. 


MILK  FAT  FROM  CARBOHYDRATES  425 

the  healthy  adult  individual  that  he  should  really  have  some- 
thing to  eat  (a  postulate  which  unfortunately  in  this  best  of 
all  worlds  is  apparently  very  incompletely  satisfied)  than 
that  the  food,  provided  in  a  general  way  it  is  palatable, 
should  have  any  particular  fixed  composition.  How  often 
has  the  author  been  amazed  at  the  patience  shown  by  his  col- 
leagues in  active  medical  practice  toward  the  very  silly 
questions  about  diet  with  which  old  ladies  of  both  sexes  are 
in  the  habit  of  plying  them  in  their  anxiety  for  their  relatives 
or  from  pure  love  of  asking  questions.  But  it  is  a  very  dif- 
ferent matter  when  we  are  dealing  with  the  feeding  of  in- 
fants. Here  there  is  room  for  the  most  painstaking  care 
and  attention  from  a  practical  standpoint.  And  it  is  par- 
ticularly important  that  the  physician  keep  constantly  before 
him  the  fact  that  the  infant's  supply  of  fat  is  directly  depen- 
dent upon  the  food  which  is  ingested  by  the  nurse  and  upon 
the  character  of  her  fat  deposits.  This  is  no  "nursery 
tale";  it  is  a  scientifically  proved  fact.  Thus,  often  the 
trouble  met  in  changing  wet  nurses  may  in  the  last  count 
be  connected  with  the  biochemistry  of  fat ;  and  there  is  jus- 
tice in  the  demand  that  in  the  first  place  the  milk  of  nursing 
women  be  kept  constant  by  selection  of  an  appropriate  fat- 
mixture,  and  again  that  by  proper  feeding  of  cows  a  milk  be 
produced  with  fat  similar  to  the  fat  of  human  milk.74  In 
spite  of  the  enormous  extent  of  milk  literature,  the  details 
of  which  cannot  possibly  be  entered  into  here,  a  great  deal 
of  work  remains  to  be  done  before  we  can  clearly  appreciate 
how  far  race,  heredity,  mode  of  nutrition,  sexual  activity, 
season,  calory-requirements  of  the  growing  body,  etc.,  affect 
the  composition  of  milk.75 

Origin  of  Milk  Fat  from  the  Carbohydrates  of  Food. — 
A  portion  of  the  fat  in  milk  doubtless  comes  from  the  carbo- 
hydrates of  food.  Thus  an  experiment  upon  a  cow  fed  for 
three  months  on  material  poor  in  fat  (hay  and  grain-food 

74  Engel  and  Plaut,  Wiener  klin.  Wochenschr.,  1906,  No.  898. 

75  Cf.  G.  von  Wendt,  Skandin.  Arch.  f.  Physiol.,  21,  89.  1909. 


426  ORIGIN  OF  MILK  FAT 

from  which  the  oil  had  been  removed)  showed  that  in  this 
period  the  animal  produced  in  her  milk  about  fifty  pounds 
more  fat  than  she  consumed  with  her  food.  And  yet  the 
cow  had  become  much  fatter;  the  actual  amount  of  newly 
formed  fat  must,  therefore,  have  been  much  more  than  this. 
The  extent  of  protein  decomposition,  determined  by  the 
nitrogen  output,  was  at  the  same  time  far  from  being  suf- 
ficient to  explain  in  any  degree  the  new  formation  of  fat. 
The  bulk  of  the  latter  was  certainly  derived,  therefore,  from 
the  carbohydrates  of  the  food.76 

Lower  Fatty  Acids  in  Müh. — Besides  the  typical  higher 
fatty  acids  (palmitic,  stearic  and  oleic  acid)  there  are  also 
small  quantities  of  the  lower  fatty  acids  in  milk,  the  presence 
of  which  is  the  more  interesting  because  it  offers  a  very  im- 
portant and,  as  far  as  the  author  knows,  hitherto  little  con- 
sidered suggestion  as  to  the  nature  and  the  method  actually 
followed  by  physiological  catabolism  of  the  higher  fatty  acids 
in  the  economy.  It  is  certainly  not  a  matter  of  accident  that 
only  normal  fatty  acids  with  unbranched  chains  and  an  even 
number  of  carbon  atoms  are  to  be  found  along  with  the 
higher  fatty  acids  in  milk,  namely,  myristic  acid,  C14 ;  lauric 
acid,  C12;  capric  acid,  C10;  caprylic  acid,  C8;  caproic  acid, 
Ce,  and  butyric  acid,  C4.77  Elsewhere,  too,  we  find  precisely 
these  same  normal  fatty  acids  with  paired  carbon  atoms 
(considering  here  the  acids  with  more  than  three  carbon 
atoms)  emerging  in  all  sorts  of  places  from  the  sea  of 
metabolism.   Thatwe  once  ina  whilemeet withisobutyric  acid, 

CH2V  ,  .         .     .     .        . .     CH3X 

>CH— COOH,    and  isovalerianic  acid,  >CH— CH2— COOH, 

CH3/  CH/ 

is  not  of  any  special  moment,  because  these  may  be  regarded 

78  W.  Jordan  and  C.  G.  Jenter,  New  York  Agric.  Exp.  Station  Bulletin,  1897. 

"  The  only  seeming  exception  to  this  rule  known  to  the  author,  a  statement 

CH3v 
of  Chevreul  as  to  the  occurrence  of  isobutylacetic  acid,  _>CH — CH2 — 

CH2 — COOH,  and  of  isovalerianic  acid  in  cow's  butter,  may  not  be  held  as 
of  very  great  importance  when  we  remember  the  great  age  of  the  observation, 
almost  a  century.    Cf.  W.  E,.  Raudnitz,  1.  c,  p.  260. 


SEBACEOUS  GLANDS  AND  COCCYGEAL  GLAND     427 


as  protein  derivatives  (from  the  branched  chain  of  leucin, 
CHJN 


CH— CH2— ch.nh2— COOH)^  In  the  author's  opinion  the  oc- 


currence of  the  normal  acids,  C4,  C6,  C8,  C10,  C12,  C14,  in 
the  milk  is  very  suggestive  of  the  possibility  that  they  may 
be  due  to  an  oxidation  reduction  from  the  typical  higher 
fatty  acids,  the  long  chain  of  the  latter  being  gradually  short- 
ened, each  time  by  two  carbon  atoms  by  oxidation  at  the 
/?-position,  following  Knoop's  idea  (vide  supra,  p.  392) : 


CH» 
CH2 

CH2 

I 
CH2 

CH2 

COOH 


CH2 

CH2 

I 
CH2 

CH.OH 

CH2 

I 
COOH 


CH2 

I 
CH2 

I 
CH2 

I 
COOH 


CH2 
CH.OH 

CH2 

I 
COOH 


CH2 
COOH. 


Sebaceous  Glands  and  Coccygeal  Gland. — In  attempting 
to  understand  the  function  of  the  mammary  glands  the  idea 
that  they  are  really  modified  sebaceous  glands  is  not  without 
significance.  A  number  of  the  lower  mammals  (as  the 
monotremes)  have  instead  of  the  mammary  glands  a  large 
number  of  small  dermal  glands  and  the  offspring  lick  the 
surface  of  the  abdomen  instead  of  sucking.  It  is  interesting, 
too,  to  know  that  in  the  material  secreted  by  ordinary 
sebaceous  glands  casein  has  been  recognized. 

The  coccygeal  gland  of  water  fowl  corresponds,  too,  in  its 
development,  structure  and  function,  to  a  modified  sebaceous 
gland.  Its  fatty  secretion,  however,  according  to  Röhmann, 
is  not  ordinary  neutral  fat,  but  consists  for  the  most  part  of 
esters,  combinations  of  fatty  acids  with  octadecylalcohol 
(derived  by  oxidation  from  oleic  acid  and  stearic  acid).  Fats 


TS  Literature  upon  The  Occurrence  of  Fatty  Acids  in  the  Body:    W.  Glikin, 
Handb.  d.  Biochem.,  1,  95-102,  1909. 


428  ORIGIN  OF  MILK  FAT 

foreign  to  the  birds'  economy  may,  just  as  in  milk,  pass  into 
the  secretion  of  the  coccygeal  gland.79 

Haptogenic  Membranes. — In  conclusion  a  few  words  may 
be  devoted  to  the  old  question  as  to  the  form  in  which  the 
fat  exists  in  milk  and  the  nature  of  the  much  discussed 
haptogenic  membranes  which  surround  the  fat  globules. 
The  contention  on  this  subject  took  its  inception  in  the 
observations  of  Ascherson  in  1840 ;  and  it  is  not  settled  to- 
day. The  physicist  Quincke  took  the  position  that  the  cover- 
ing of  the  fat  globules  consisted  merely  of  a  layer  of  protein 
condensed  about  the  globules;  by  surface  tension ;  V.  Storch 
and  a  number  of  other  observers  (as,  recently,  W.  Völtz80 
and  H.  Bauer  81 )  held  that  the  haptogenic  membrane  is  of  a 
gelatinous,  relatively  firm  character,  often  compared  to  the 
stroma  of  red  blood  cells.  Völtz  refers  with  emphasis  to  the 
fact  that  if  milk  globules  passed  through  a  column  of  water 
are  skimmed  off  from  the  surface  of  the  water  and  centrif- 
ugated,  invariably  in  a  short  time  the  coverings  of  the  milk 
globules  are  largely  precipitated  and  collect  as  a  firm  (not  a 
gelatinous)  substance  at  the  bottom.  When  the  fat  is  re- 
moved by  use  of  a  Soxhlet  apparatus  the  haptogenic  mem- 
branes remain  behind.  Under  the  microscope  the  isolated 
coverings  show  very  irregular  appearances.  Analysis  and 
hydrolysis  (a  few  decigrams  may  be  obtained  from  a  liter 
of  milk)  show  that  they  contain  a  very  large  proportion  of 
ash  along  with  protein,  and  consist  not  only  of  casein  but  also 
of  calcium  salts  of  the  fatty  acids.82  All  this  does  not  in  the 
author's  opinion  prove  that  they  are  organized,  preformed 
structures  in  the  milk.     It  may  easily  be  fancied  that  a  layer 

™~F.  Röhmann  (Breslau),  Hofmeister's  Beitr.,  5,  110,  1904. 

80  W.  Völtz  (Zoöteeh.  Instit.,  Agric.  High  School,  Berlin),  Pfluger's  Arch., 
102,  373,  1904;    Handb.  d.  Biochem.,  3',  394,  1910. 

81 H.  Bauer  (Instit.  of  Dairying,  Agric.  High  School,  Vienna),  Biochem. 
Zeitschr.,  32,  362,  1911. 

62  E.  Abderhalden,  and  W.  Völtz,  Zeitschr.  f.  physiol.  Chem.,  59,  13,  1909; 
Bredenberg  (N.  Zuntz's  Lab.),  Abhandl.  d.  Agrikulturwissenschaftl.  Ges.  in 
Finnland,  H.  4,  Helsingfors,  1912,  cited  in  Centralbl.  f.  d.  ges.  Biol.,  1912, 
No.  2011. 


HAPTOGENIC  MEMBRANES  429 

of  protein,  condensed  about  a  fat  globule  by  surface  tension, 
may  become  still  more  condensed  by  these  very  processes  of 
separation  (passing  through  a  layer  of  water,  centrifuga- 
tion),  rendering  it  a  firm  and  separable  structure.  That 
coagulative  phenomena  may  take  place  in  the  adsorbed 
surface  layer  of  a  colloidal  solution  has  been  repeatedly 
emphasized,  and  by  Kreidl  and  Lenk  for  milk  especially.83 
These  latter  writers  have,  too,  proposed  a  very  simple 
experiment,  which  in  the  author  's  opinion  distinctly  contra- 
dicts the  idea  of  an  organized  nature  for  the  haptogenic  mem- 
branes. It  is  well  known  that  the  theory  of  the  haptogenic 
membrane  is  based  on  the  fact  that  fat  is  not  separable  from 
cow  's  milk  by  merely  shaking  with  ether,  but  can  be  accom- 
plished only  after  first  treating  the  milk  with  potassium 
hydrate  solution.  This  has  been  interpreted  as  indicating 
that  the  potash  solution  dissolves  the  "membrane"  which 
encloses  the  fat  globule  and  protects  it  from  the  penetration 
of  the  ether.  Kreidl  and  Lenk,84  however,  have  found  that 
when  a  drop  of  milk  is  placed  on  Lösch  carton  it  divides  into 
three  concentric  zones  as  the  result  of  capillary  adsorption ; 
in  the  central  zone  the  suspended  fat  remains  behind,  in  the 
middle  zone  the  imperfectly  dissolved  casein,  while  the  water 
and  fully  dissolved  materials  (as  sugar)  pass  furthest  and 
are  to  be  found  in  the  outer  ring.  If  the  milk  be  rich  in 
fat  there  remains  in  the  centre  a  large  proportion  of  a  butter- 
like material,  which  is  readily  soluble  in  ether  (particularly 
apropos  to  the  matter  in  hand).  To  the  writer's  mind  this 
seems  altogether  at  variance  with  the  assumption  of  an 
organized  nature  of  "milk-stromata"  or  "haptogenic  mem- 
branes." It  would  be  impossible  to  think  that  they  are 
stripped  away  from  the  individual  fat  globules  in  the  course 
of  distribution  of  the  milk  in  the  Lösch  paper.  The  facts 
probably  are  that  the  insolubility  of  the  milk  fat  in  ether  is 
connected  with  the  presence  of  ultra  microscopic  particles  of 

83  A.  Kreidl  and  E.  Lenk  (Vienna),  Pflüger's  Arch.,  1^1,  558,  1911. 

84  L.  c,  pp.  543-549. 


430  ORIGIN  OF  MILK  FAT 

casein  in  the  milk.  According  to  K.  Liesegang  the  addition 
of  the  ether,  by  precipitating  the  casein  emulsion,  produces 
the  formation  of  the  membrane  as  an  artefact.  When  potash 
solution  is  added  the  ether  does  not  meet  an  emulsion  of 
casein,  but  a  solution  of  casein,  and  therefore  cannot  induce 
membrane  formation.  It  has  been  long  known  that  the  fat 
of  human  milk,  in  contrast  to  that  of  cow's  milk,  is  directly 
soluble  in  ether;  this,  according  to  Kreidl  and  Lenk,85  de- 
pends on  the  fact  that  casein  is  not  present  in  human  milk  in 
the  form  of  ultramicroscopically  demonstrable  particles,  but 
in  solution. 

85  A.  Kreidl  and  E.  Lenk    (Verhandl.  d.  morpholog-physiol.  Ges.,  Wien), 
Centralbl.  f.  Physiol.,  25,  No.  12,  1911. 


CHAPTEE  XVIII 
ACETONE  BODIES 

That  the  acetone  bodies  are  introduced  here  in  immedi- 
ate connection  with  our  studies  of  fat  metabolism  is  because 
of  the  fact  that  these  mysterious  substances,  which  appear  in 
an  apparently  unregulated  way,  now  here,  now  there,  upon 
the  surface  of  the  tide  of  metabolism,  and  which  at  one  or 
other  time  were  referred  now  to  one,  now  to  another  of  the 
principal  types  of  foods,  must,  in  consonance  with  the  pres- 
ent status  of  science,  be  regarded,  at  least  principally,  as 
catabolic  products  of  fat. 

In  the  group  of  acetone  bodies  we  recognize,  as  is  well 
known,  ß-oxybutyric  acid,  acetoacetic  acid  and  acetone,  the 
relative  chemical  connection  of  which  seems  to  be  that  in- 
dicated in  the  following  schema : 

/9-OXTBUTYRIC   ACID  ACETOACETIC   ACID  ACETONE 

CH,  CH, 

CH, 


CH— OH  CO 

i: 


_^         | >        CO 

H2  — H2  CH2  — C02 

I  CH8. 

COOH  COOH 

These  accumulate  in  the  body  in  certain  pathological  con- 
ditions, notably  in  diabetic  coma. 

Without  entering  into  the  historical  development  of  the 
subject  of  the  acetone  bodies,  the  author  may  with  pro- 
priety in  introduction  briefly  outline  the  basis  for  assum- 
ing that  there  is  a  connection  between  them  and  the  breaking 
down  of  the  higher  fatty  acids  in  the  body.1 

Relation  of  the  Formation  of  Acetone  Bodies  to  the  Cor- 
poreal Fat  and  to  that  of  the  Food. — It  may  be  stated  first 

1  Literature  upon  the  Relation  of  the  Acetone  Bodies  to  Fat  Destruction 
in  the  Economy:  A.  Magnus-Levy,  Noorden's  Handb.  d.  Pathol,  d.  S'toffw.,  2d 
ed.,  1,  184-188,  1906 ;  A.  Magnus-Levy  and  L.  F.  Meyer,  Handb.  d.  Biochem.,  4, 
483-484,  1909;  0.  Porges,  Ergebn.  d.  Physiol.,  10,  8-11,  1910;  C.  Oppenheimer 
and  L.  Pincussohn,  Handb.  d.  Biochem.,  k,  697-702,  1911. 

431 


432  ACETONE  BODIES 

that  no  parallelism  has  been  recognized  between  the  excre- 
tion of  acetone  bodies  and  the  reduction  of  the  body  protein 
(reckoned  from  the  nitrogen  output),  but  that  such  paral- 
lelism has  been  noted  in  case  of  reduction  of  the  body-fat  in 
starvation,  diabetes,  cancer,  phosphorus  poisoning,  and 
other  pathological  conditions.  Thus  Brugsch  observed 
abundant  excretion  of  acetone  bodies  in  case  of  a  profes- 
sional faster  who  in  spite  of  the  low  nutrition  to  be  expected 
in  his  calling,  had  a  magnificent  fatty  panniculus ;  whereas  in 
a  woman  in  extreme  emaciation,  who  had  not  the  slightest 
visible  trace  of  body  fat  left,  no  evidence  of ' '  acidosis ' '  could 
be  noted.2  The  striking  inhibitory  influence  manifested 
upon  the  excretion  of  acetone  bodies  by  exhibition  of  carbo- 
hydrates is  naturally  explained  by  the  consequent  diminu- 
tion of  the  destruction  of  the  body  fat.  Magnus-Levy  noted 
in  a  case  of  diabetic  coma  the  excretion  of  such  large  amounts 
of  acetone  bodies  (more  than  one-third  of  a  kilogram  esti- 
mated as  oxybutyric  acid,  in  the  course  of  three  days)  that 
even  if  the  total  carbon  of  the  coincident  protein  destruction 
were  converted  into  oxybutyric  acid  (which  naturally  was 
not  the  case)  it  would  not  have  been  equivalent.  This  ob- 
servation alone  would  permit  scarcely  any  other  interpreta- 
tion than  that  the  acetone  bodies  originate  from  the  fat.3 

Another  and  for  us  an  important  fact  is  that  frequently 
the  pathological  excretion  of  acetone  bodies  is  associated 
with  a  high  grade  of  lipaemia,  in  evidence  of  mobilization  of 
the  fat  from  the  depots.  It  was  pointed  out  above  that  the 
blood  may  be  so  rich  in  fat  in  diabetic  coma  as  to  look  like 
chocolate  and  cream. 

Origin  of  the  Acetone  Bodies  from  the  Lower  Fatty  Acids 
with  Even  Carbon  Atom  Chain. — There  are  a  number  of 
observations  of  an  increased  excretion  of  acetone  bodies 


2  Brugsch,  Zeitschr.  f .  exper.  Pathol.,  1,  426,  1905. 
*  A.  Magnus- Levy,  1.  c,  p.  184. 


ORIGIN  OF  ACETONE  BODIES  433 

after  ingestion  of  dietary  fat.4  That  this  sequence  does  not 
evince  itself  in  a  more  striking  manner  is,  in  the  author's 
opinion,  due  to  the  fact  that  we  are  not  always  able  to  insure 
an  increased  utilization  of  fat  by  increasing  the  ingestion  of 
fat,  as  the  excess  is  generally  simply  deposited.  Twice  in 
the  course  of  these  lectures  (Chapter  XVI,  p.  392  and  Chap- 
ter XVII,  p.  427)  occasion  has  been  taken  to  refer  to  the 
important  discoveries  of  F.  Knoop  and  G.  Embden  which 
indicate  (with  great  probability,  in  the  author's  opinion) 
that  the  catabolism  of  the  normal  fatty  acids  proceeds  with 
a  two-by-two  loss  of  carbon  atoms  from  the  carboxyl  end. 
It  has  been  pointed  out  above  that  there  are  no  essential 
difficulties  in  the  belief  that,  beginning  with  the  higher  fatty 
acids,  by  a  continuous  shortening  of  the  carbon  chain  we 
finally  obtain  butyric  acid,  from  which  we  get  oxybutyric 
acid,  and  from  this  then  diacetic  acid  and  acetone. 


CH, 
H2  CHS 


i 


CH2  CH,  CH, 

I  I  I 

CH2  CH2  CH2 

CH,  — >    CH2      — >■    CH, 

I  I  I 

CH,  CH2  COOH 

CH,  COOH 


CH, 

1 

CH, 

i 

CH.OH 

1 

CO 

CH, 

i 

CH,      — > 

CH,      — 

1 

1 
>    CO 

COOH 

COOH 

CH, 

i 


OOH 

It  is  very  well  worth  noting  and  is  established  by  many 
observations  on  diabetic  human  beings  and  animals  5  that 
administration  of  butyric  acid  (C4)  and  caproic  acid  (C6) 

*  Geelmuyden ;  L.  Schwarz;  E.  P.  Joslin  (Harvard  Univ.,  Boston),  Jour, 
of  Med.  Research,  12,  433,  cited  in  Biochem.  Centralbl.,  3,  No.   828,    1904; 

E.  Allard  (Minkowski's  Clinic,  Greifswald),  Arch.  f.  exper.  Pathol.,  57,  1,  1907; 

F.  Steinitz,  Centralbl.  f.  innere  Med.,  25,  81,  1904;    Forssner    (Stockholm), 
Skandin.  Arch.,  23,  305,  1910;    cf.  therein  the  older  Literature. 

6  Geelmuyden,  Rumpf,  L.  Schwarz,  Lob,  Strauss  and  Philippsohn ;  cf . 
Magnus-Levy,  1.  c,  p.  185;  L.  Schwarz  (Prague),  Deutsch.  Arch.  f.  klin.  Med., 
76,  233,  1903;  J.  Bär  and  L.  Blum  ( S'trassburg ) ,  Arch.  f.  exper.  Pathol.,  55,  89, 
1906;    59,  321,  1908;    62,  129,  1910. 

28 


434  ACETONE  BODIES 

appreciably  increase  the  elimination  of  acetone  bodies,  and, 
too,  in  greater  proportion  than  the  exhibition  of  the  higher 
fatty  acids.  A.  Löwy  and  R.  Ehrmann  saw  a  deep  and  per- 
sistent coma  occur  in  butyric  acid  poisoning,  while  in  poison- 

ing  with  isobutyric  acid,       *  J>CH— COOH  (the  branched  chain 

of  which  is  unable  to  pass  over  into  ß-oxy butyric  acid),  noth- 
ing in  the  least  comparable  was  noted.6 

C.  von  Noorden  recommends  that  the  butter  intended  for 
diabetics  be  thoroughly  worked  with  water  in  order  to  re- 
move the  butyric  acid. 

In  close  consonance  with  the  above  conception  of  fatty 
acid  catabolism  is  the  fact  that  only  the  normal  fatty  acids 
with  an  even  number  of  carbon  atoms  are  productive  of 
acetone  bodies,  as  Embden  found  experimentally  by  perfu- 
sion of  the  liver,  and  Bär  and  Blum  found  in  diabetics  (vide 
supra,  p.  393). 

As  a-aminoacids  in  catabolism  are  first  deprived  of  one 
member  it  can  be  easily  understood  why  a  -aminovalerianic 
acid  (but  not  a-aminobutyric  acid  or  normal  a-aminocaproic 
acid)  may  be  classed  with  the  acetone  producers : 7 

CHj 

CH2  CH3  CHj 

I  I  I 

CH,  CH2  CH.OH 

CH.NH2  CHj  CH2 

COOH  COOH  COOH. 

Possibility  of  Disintegration  of  the  Longer  Fatty  Acid 
Chains  into  Short  Parts. — The  above  presented  mode  of 
formation  of  oxybutyric  acid  from  higher  fatty  acids  indi- 
cates one  possibility  of  this  connection,  but  not  the  only  one 

•A.  Löwy,  Berliner  physiol.  Ges.,  Dec.  16,  1910;  A.  Löwy,  together  with 
R.  Ehrmann  and  P.  Esser,  Zeitschr.  f.  klin.  Med.,  72,  496,  500,  502,  1911. 

'G.  Embden  and  A.  Marx,  Hofmeister's  Beitr.,  11,  318,  1908;  J.  Bär 
and  L.  Blum,  1.  c. 


DISINTEGRATION  OF  FATTY  ACID  CHAINS        435 

by  any  means.  It  is  stated  that  in  severe  diabetes  some- 
times there  are  excreted  a  greater  number  of  molecules  of 
oxybutyric  acid  than  can  be  accounted  for  by  the  number  of 
molecules  of  fatty  acids  which  are  in  course  of  decomposi- 
tion. As  a  matter  of  fact  it  is  very  difficult,  if  at  all  possible, 
to  estimate  correctly  the  number  of  the  latter  in  our  calcula- 
tions in  metabolic  experiments.  However,  were  this  the 
case  it  would  strongly  indicate  that  the  long  fatty  acid  chains 
are  not  reduced  step  by  step  until  they  come  to  the  four 
carbon  atom  stage  and  are  changed  into  butyric  acid;  we 
would  have  to  assume  that  the  chain  is  first  broken  into  a 
number  of  segments,  each  of  which  is  transformed  into 
butyric  acid.8  Ernst  Friedmann 9  found  in  F.  Hofmeister 's 
laboratory  that  (of  a  number  of  substances  with  two-armed 
carbon  chain  subjected  to  investigation)  acetaldehyde  alone 
was  synthesized  into  diacetic  acid  in  perfusion  of  the  liver. 
As  two  molecules  of  acetaldehyde  are  very  readily  condensed 
into  aldol  and  this  in  perfusion  experiments  is  capable  of 
transformation  into  diacetic  acid,  it  is  not  unlikely  (follow- 
ing the  conceptions  of  Magnus-Levy10  and  Spiro)  that  the 
reactions  may  be  represented  by  the  following  formulae : 

ACETALDEHYDE  ALDOL 

CH,.COH  +  CH,.COH    -     CH3.CH(OH).CH2.COH 

ALDOL  Ö-OXYBUTYRIC   ACID 

CH,.CH(OH).CH2COH  +  O    =    CH3.CH.OH.CH2.COOH. 

It  might  also  be  imagined  that  the  fatty  acid  chains  are 
primarily  broken  up  into  links  with  only  two  carbon  atoms 
each,  and  that  these  then  become  synthesized  by  way  of 
acetaldehyde  into  /3-oxybutyric  acid. 

8  A.  Magnus-Levy,  Arch.  f.  exper.  Pathol.,  40,  433,  1901. 
E.  Friedmann    (F.  Hofmeister's  Lab.,  Strassburg),  Hofmeister's   Beitr., 
11,  202,  1908. 

10  A.  Magnus-Levy,  Die  Oxybutyrsäure  und  ihre  Beziehungen  zum  Coma 
diabeticum,  Leipzig,  F.  C.  W.  Vogel,  1899,  p.  78. 


436  ACETONE  BODIES 

Again,  ethyl  alcohol  may  give  rise  to  diacetic  acid  in 
experimental  perfusion  of  the  liver  (probably  by  way  of  ace- 
taldehyde).11 

Is  ß-oxybutyric  Acid  a  Product  of  Normal  Metabolism? — 
Another  important  question,  which  for  the  present  must  be 
accepted  as  an  open  one,  is  whether  ß-oxybutyric  acid  is  to  be 
regarded  as  distinctly  a  product  of  normal  or  only  of  patho- 
logical metabolism.  The  author's  early  deceased  friend, 
Leo  Schwarz,  who  insured  for  himself  a  lasting  place  in 
science  by  his  investigations  upon  diabetes,  long  since  satis- 
fied himself  that  ingested  ß-oxybutyric  acid  is  metabolized 
with  more  difficulty  by  diabetics  than  by  normal  human  be- 
ings (whereas  ingested  acetone  is  apparently  attacked  with 
equal  difficulty  by  the  normal  and  by  the  diabetic  economy) . 
Therefore  it  can  scarcely  be  thought  that  acetone  plays  any 
important  role  in  normal  metabolism,  as  it  would  other- 
wise necessarily  appear  also  normally.  But  one  cannot  ex- 
clude the  possibility,  in  case  of  ß-oxybutyric  acid,  of  its 
occurrence  as  an  intermediate  product  of  physiological 
metabolism.  If  this  be  true,  then  an  increased  excretion  of 
this  substance  should  be  due  to  the  fact  that  its  destruction 
in  the  economy  is  diminished  under  pathological  conditions. 
It  might  be,  too,  that  in  pathological  conditions  the  fault 
lies  in  an  increased  formation  of  the  acetone  bodies.  Emb- 
den  found  in  his  perfusion  experiments  that  the  liver  of  the 
dog  with  pancreatic  diabetes  undergoes  a  change  in  its 
normal  function  of  forming  diacetic  acid,  in  the  form  of  a 
decided  exaggeration.12  As  he  further  found  that  the  ability 
of  the  surviving  liver  to  induce  disappearance  of  diacetic 

11 N.  Masuda  (G.  Embden's  Lab.),  Biochem.  Zeitscbr.,  45,  140,  1912.  From 
another  standpoint  alcobol  is  to  be  classed  with  the  antiketogens  along  with 
other  substances,  as  tartaric  acid  and  glycerol-aldehyde,  which,  according  to 
experimental  conditions,  can  either  serve  as  a  source  for  the  acetone  bodies  or 
act  to  inhibit  the  formation  of  acetone.  (Cf.  G.  Embden  and  K.  Ohta,  Biochem. 
Zeitschr.,  Jt5,  170,  1912;  R.  T.  Woodyatt,  Jour.  Amer.  Med.  Assoc,  55,  2109, 
cited  in  Jahresber.  f.  Tierchem.,  //0,  818,  1912.) 

12  G.  Embden,  and  L.  Lattes,  Hofmeister's  Beitr.,  11,  327,  1908. 


DERIVATION  OF  ACETONE  BODIES  437 

acid  is  not  abnormally  diminished  for  the  depancreatized 
dog,  he  thought  that  the  increased  excretion  of  acetone 
bodies  in  case  of  the  diabetic  individual  is  not  due  to  a 
diminished  catabolism  of  these  substances  but  more  likely 
to  their  increased  formation.  This  result,  however,  cannot 
be  accepted  as  definitive,  as  it  is  not  as  yet  proved  that 
the  loss  of  diacetic  acid  noted  in  experiments  with  the 
ground-up  hepatic  tissue,  is  consistent  with  the  intravital 
catabolism  of  diacetic  acid.14 

Derivation  of  Acetone  Bodies  from  Compounds  ivith 
Branched  and  Cyclical  Chains. — Thus  far  we  have  been  con- 
sidering only  the  relations  of  the  acetone  bodies  to  the  nor- 
mal fatty  acids.  However,  the  acetone  bodies  have  also  been 
traced  back  to  compounds  with  branched  and  cyclic  nuclei, 
like  leucin,  tyrosin  and  Phenylalanin;  and  the  question 
naturally  arises  whether  these  cleavage  products  of  the 
protein  molecule  can  also  serve  as  a  source  of  the  acetone 
bodies  in  the  living  body.  The  author  will  attempt  to  pre- 
sent the  existing  status  of  the  problem,  which,  thanks  to  the 
studies  of  Embden,14  Bär  and  Blum,15  Borchhardt  and 
Lange,16  Friedmann,17  and  other  authors  18  has  been  con- 
siderably clarified,  as  well  as  he  understands  it,  and  requests 
special  attention  to  the  points  involved  that  confusion  may  be 
avoided. 

13  G.  Embden  and  L.  Michaud,  Hofmeister's  Beitr.,  11,  331,  1908,  and 
Biochem.  Zeitschr.,  13,  262,  1908;  cf.  also  E.  Allard  (Minkowski's  Clinic, 
Greifswald),  Arch.  f.  exper.  Pathol.,  59,  380,  1908. 

14  G.  Embden,  in  collaboration  with  Almagia,  Kalberlah,  Marx,  Salomon, 
Schmidt,  Engel,  Wirth  and  Sachs,  Hofmeister's  Beitr.,  8,  129,  1906;  11,  323, 
847,  1908;    Biochem.  Zeitschr.,  21,  20,  27,  1910. 

15  J.  Bär  and  Blum,  1.  c. 

M Borchhardt  and  Lange  (Weintraud's  Clinic),  Hofmeister's  Beitr.  9,  116, 
1907. 

17  E.  Friedmann  (Berlin),  Hofmeister's  Beitr.,  11,  365,  371,  1908. 

13  A.  Baumgartner  and  H.  Popper  (E.  Freund's  Lab.,  Vienna),  Centralbl. 
f.  Physiol.,  20,  No.  12,  1906;  G.  Forssner  (Stockholm),  Skandin.  Arch.  f. 
Physiol.,  25,  338,  1911;  E.  M.  Fittipaldi  (Naples),  Centralbl.  f.  Stoff w.,  5,  161, 
1910;    cf.  also  Literature:    O.  Porges,  Ergebn.  d.  Physiol.,  10,  17,  et  seq.,  1910. 


438  ACETONE  BODIES 

The  fact  of  the  matter  is  that  leucin  is  recognized  as 
capable  of  serving  in  the  economy  as  a  source  of  acetone 
bodies.  As  long  as  it  was  known  only  that  acetone  could 
be  produced  from  it  by  perfusion  through  the  liver  it  could 
be  supposed  that  this  occurred  by  the  separation  of  the  leucin 
nucleus  at  the  position  of  branching  and  the  entrance  of  an 
atom  of  oxygen  at  this  point : 
CH3    CH3 

CH  CH3     CH, 

I  \  /     ■ 

CH2  — >-  CO 

CH.NH, 

I 
COOH 

precisely  as  we  suppose  that  acetone  is  formed  in  oxidation 

of  proteins  with  peroxide  of  hydrogen  (Vol.  I  of  this  series, 

p.  23,  Chemistry  of  the  Tissues).      This  view,  however, 

was  seen  to  be  incorrect  after  it  was  recognized  that  diacetic 

acid  in  this  case  also  serves  as  a  forerunner  of  acetone.    It  is 

CH3\ 
now  held  that  isoamylamine,         ^CH— CH,— CH,.NH2,  lsovaler- 

CH  s.  CH3/ 

aldeyde,  >CH— CH2— COH,       and    isovalerianic    acid, 

CH,/ 

OTT  \ 

>CH— CHj— COOH,      can  contribute  to  the  formation  of 
CH,/ 
acetone  bodies  in  the  economy,  as  well  as  ethylbutyric  acid, 

CH,  \  .,...,  CH,\ 

>CH— CH,— COOH,  ß-oxjis ovaler iamc  acid,         >C(OH)— CH, 
C2H6/  CH,/ 

—COOH,  dimethylacrylic  acid,       \c  =  CH— COOH,and  crotonic 

CH3/ 
acid,  CH3— CH=CH— COOH.  In  the  first  mentioned  instances  a 

possible  arrangement  might  be  made  by  which  one  of  the 
alkyl  groups  above  the  position  of  branching  is  thrown  off 
and  replaced  by  a  hydroxyl  radicle : 
CH,    CH,  CH, 

CH  CH.OH 

CH,  CH, 

COOH  COOH. 


CARBOHYDRATE  DEFICIENCY  AND  ACIDOSIS     439 

This  possible  mode  of  explanation,  unless  forced,  fails,  how- 

.  CHa-CHj— CH— COOH, 

ever,  m  case  of  a-methylbutyric  acid,  i 

CH3 

from  which  by  analogous  procedure  a-oxybutyric  acid  should 

arise.    There  is  particularly  no  possibility  of  explaining  by 

this  means  the  fact  that  a  tricarbon  complex  like  glycerol 19 

and  that  certain  benzol  derivatives,  whose  ring  is  subject  to 

disintegration  in  the  animal  body,  like  Phenylalanin,  C6H5  - 

CH2  -  CH.NH2  -  COOH,  and  tyrosin,    /H 

CeHr- CH*— CH.NHr-  COOH , 

must  be  classed  among  acetone  forming  substances.  And  as 
the  formation  of  acetone  bodies  from  these  latter  can  be  con- 
ceived synthetically  possible  only  from  groups  containing 
but  few  carbon  atoms,  the  question  at  once  arises  whether  in 
case  of  the  formation  of  ß-oxybutyric  acid  from  normal 
higher  fatty  acids  the  process  may  not  follow  pretty  much 
the  line  of  explanation  proposed  by  Friedmann.  This  in  the 
author's  opinion  can  be  made  to  fit  in,  too,  with  Embden's 
observation  upon  the  contrast  between  acids  with  even  and 
with  odd  numbers  of  carbon  atoms.  It  is,  however,  quite  as 
likely  that  the  development  of  /?-oxybutyric  acid  in  the 
economy  takes  place  in  different  ways :  that  it  may  be  formed 
from  stearic  acid,  for  example,  by  "two-atom  shortening 
of  the  chain, ' '  but  from  tyrosin  by  way  of  synthesis  of  two- 
carbon-atom  compounds. 

Carbohydrate  Deficiency  and  Acidosis. — In  what  relation, 
next,  does  the  appearance  of  the  acetone  bodies  stand  to  the 
carbohydrate  exchange  in  the  economy?  Allusion  has  been 
made  above  to  the  distinct  "antiketogenic"  influence  of 
carbohydrates,  along  with  the  statement  that  this  may  be 
fully  explained  on  the  basis  of  an  inhibition  of  fat  decom- 
position because  of  the  combustible  material  thus  introduced 
into  the  body.  To  the  author's  way  of  thinking,  this  makes 
all  other  complicated  theories  entirely  superfluous,  espe- 

UF.  Reach  (A.  Durig's  Lab.,  Vienna),  Biochem.  Zeitsehr.,  Ik,  279,  1908. 


440  ACETONE  BODIES 

cially  such  theories  as  that  of  Geelmuyden,  who  first  urged 
the  idea  that  carbohydrates  and  acetone  bodies  unite  syn- 
thetically to  form  a  combination  which  is  essential  for  the 
further  exchange  of  the  acetone  bodies,  and  then  undertook 
to  show  that  acetone  bodies  are  convertible  in  the  body  into 
carbohydrates,  and  that  they  constitute  a  transition  stage  in 
the  supposed  transformation  of  fat  into  carbohydrates.  It 
seems  more  likely  that  the  observed  fact  that  subcutaneous 
injection  of  diacetic  acid  or  ß-oxybutyric  acid  in  animals 
poisoned  with  phloridzin  increases  the  output  of  sugar  in 
the  urine,  is  explicable  on  the  supposition  of  a  toxic  increase 
of  protein  decomposition,  rather  than  upon  the  assumption 
of  Geelmuyden  that  there  occurs  a  sugar  synthesis  from 
acetone  bodies.20 

According  to  J.  Bär  simple  withdrawal  of  carbohydrates 
is  followed  in  normal  human  beings  accustomed  to  a  mixed 
diet,  and  also  in  apes,  by  an  acidosis,  that  is,  by  an  excretion 
of  acetone,  diacetic  and  oxybutyric  acids,  along  with  coinci- 
dent increase  in  the  ammonia  elimination.  In  the  dog,  goat 
and  pig  acidosis  does  not  show  upon  mere  reduction  of  carbo- 
hydrate, but  is  induced  by  combining  phloridzin  intoxication 
with  fasting.21 

Diabetic  Coma. — As  is  well  known  diabetic  coma,  a  symp- 
tom complex  clearly  described  many  years  ago  by  Kussmaul, 
has  been  recognized,  especially  from  the  investigations  of 
Stadelmann  and  the  Naunyn  school,  as  an  acid  intoxication 
caused  by  an  accumulation  in  the  system  of  acetone  bodies.22 
Magnus-Levy,23  who  took  a  prominent  part  in  these  investi- 
gations, showed  that  oxybutyric  acid  appears  in  the  urine 
of  all  severe  cases  of  diabetes,  even  apart  from  the  coma, 

20  H.  C.  Geelmuyden  (Christiania),  Zeitschr.  f.  physiol.  Chem.,  41,  128, 
1904;    73,  176,  1911. 

21  J.  Bär  (Med.  Clinic,  Strassburg),  Arch.  f.  exper.  Pathol.,  54,  153,  1905. 

22  Literature  upon  Acetone  Bodies  in  Diabetic  Coma:  C.  v.  Noorden,  Handb. 
d.  Pathol,  d.  Stoffw.,  2d  ed.,  2,  69-86,  1907. 

23  A.  Magnus-Levy,  1.  c;   Arch.  f.  exper.  Pathol.,  '/I  and  Jfö. 


ALKALINE  TREATMENT  OF  DIABETIC  COMA     441 

in  very  large  amounts  (twenty  to  thirty  grams  in  the 
course  of  twenty-four  hours).  In  cases  of  coma  the  forma- 
tion of  this  acid  rises  to  an  abnormal  level,  and  coincidently 
there  is  a  lowering  of  its  combustion.  Under  such  circum- 
stances enormous  quantities  of  the  substance  may  appear  in 
the  urine  (as  much  as  160  grams  in  twenty-four  hours).  In 
the  body  of  subjects  dead  from  diabetic  coma  one  or  two  hun- 
dred grams  of  the  acid  may  be  found.  The  coma  is  regarded 
as  an  acid  intoxication,  in  which,  it  would  seem,  all  the  indi- 
vidual phenomena  are  dependent  either  directly  or  indirectly 
upon  the  accumulation  of  acid.  As  the  supply  of  alkali  which 
the  system  keeps  ready  for  the  neutralization  of  the  acids 
permeating  it  is  not  large,  these  acids  (oxybutyric  acid, 
diacetic  acid)  are  for  the  most  part  neutralized  by  ammonia, 
which  is  thus  withdrawn  from  urea  formation.  In  these 
cases,  therefore,  the  urinary  ammoniacal  elimination  serves 
as  an  approximate  index  of  the  acid  excretion.24 

Alkaline  Treatment  of  Diabetic  Coma. — Oxybutyric  acid, 
the  sites  of  production  of  which  may  be  looked  upon  as 
the  liver  and  muscles  and  perhaps  other  tissues  as  well,  pro- 
duces in  case  of  diabetic  coma,  as  indicated  by  the  observa- 
tions of  Minkowski,  F.  Kraus  and  others,  a  lowering  of  the 
alkalescence  of  the  blood  and  of  the  amount  of  carbonic 
acid  fixed  thereby  in  the  blood.25  For  this  reason  it  is  alto- 
gether logical  that  in  the  coma,  which  in  French's  opinion  is 
the  most  serious  menace  to  the  life  of  the  diabetic  subject 
(aside  from  pulmonary  phthisis),  efforts  be  made  to  an- 
ticipate it  by  a  prophylactic  alkaline  treatment.  Umber 
believes  that  in  those  cases  of  diabetes  in  which  persistence 
of  diacetic  acid  in  the  urine  can  be  recognized  by  the  ferric 
chloride  reaction,  enough  alkali  should  be  given  daily  to 
give  the  urine  an  amphoteric  reaction.     "This  frequently 

24  A.  Magnus-Levy,  Die  Oxybuttersäure  und  ihre  Beziehungen  zum  Coma 
diabeticum,  Leipzig,  J.  C.  Vogel.,  1899,  p.  83. 

25  G.  Embden  and  L.  Lattes  (Frankfurt  a.  M.),  Hofmeister's  Beitr.,  11,  327, 
190S;  H.  C.  Geelmuyden  (Christiania),  Zeitschr.  f.  physiol.  Chem.,  58,  253,. 
1909. 


442  ACETONE  BODIES 

requires  comparatively  large  amounts,  which  the  patient 
often  can  scarcely  master  .  .  .  fifteen  to  one  hundred, 
up  to  two  hundred  grams  or  more,  of  sodium  bicarbonate 
may  be  necessary  to  accomplish  the  desired  end.  ...  I 
have  never  seen  any  more  effect  from  intravenous  adminis- 
tration of  alkali  (usually  given  in  the  form  of  three  or  four 
percent,  soda  solutions)  than  from  subcutaneous  infiltrations 
of  isotonic  sodium  chloride  solutions ;  and  for  this  reason, 
like  Naunyn,  I  have  long  ago  given  up  the  former  method. 
There  is  no  question  as  to  our  ability  to  save  severe  cases 
of  diabetes  by  alkaline  treatment  in  the  face  of  an  acidosis  of 
years '  duration,  although  without  this  method  of  treatment 
this  would  be  a  matter  of  impossibility.  When  coma  is  fully 
developed  in  adults  all  effort  to  stop  it  is  in  vain;  but  in 
children  now  and  then  therapeutic  results  may  be 
obtained.26 

C.  v.  Noorden 27  is  in  the  habit  of  saying  of  these  influ- 
sions,  because  of  his  own  rich  experience,  that  any  one  who 
has  ever  witnessed  a  single  time  the  wonderful  result  pro- 
duced by  the  infusion  of  a  soda  solution  upon  a  comatose 
diabetic  subject  is  bound  to  accept  as  a  certainty  the  effec- 
tiveness of  the  alkaline  treatment.  Time  and  again  the 
patient  is  seen  waking  up  from  the  deepest  coma  while  the 
infusion  is  being  administered.  There  is  no  other  agency 
which  will  do  the  same  thing. 

Antiketogenic  Substances. — In  view  of  the  antiketogenic 
influence  of  carbohydrates,  one  should  seek  in  those  cases  in 
which  acidosis  arises  after  the  withdrawal  of  carbohydrates 
to  give  some  form  of  these  substances  adapted  to  the  diabetic 
patient.  In  Umber's  opinion  these  are  the  cases  which 
should  be  placed  upon  v.  Noorden 's  oatmeal  treatment,  by 
which  not  infrequently  it  is  possible  to  restore  tolerance  and 
remove  the  impending  danger  of  coma.28 

36  F.  Umber,  Lehrbuch  d.  Ernähr,  u.  d.  Stoffwechselkr.,  p.  231,  1909. 

27  C.  von  Noorden,  1.  c,  p.  85. 

28  F.  Umber,  1.  c,  p.  229. 


ANTIKETOGENIC  SUBSTANCES  443 

Other  substances  which  are  easily  combustible  in  the 
economy  also  have  an  antiketogenic  action,  in  the  same  way 
as  carbohydrates.  According  to  Embden  it  is  also  possible, 
in  experimental  perfusion  of  the  liver,  to  inhibit  the  forma- 
tion of  acetone  bodies  by  adding  easily  oxidizable  substances 
to  the  perfusion  fluid.  For  example,  we  may  prevent  the 
production  of  diacetic  acid  from  caproic  acid  by  introducing 
into  the  liver  valerianic  acid  (which  is  not  a  source  of  acetone 
bodies,  because  of  the  uneven  number  of  its  carbon  atoms).29 
It  is  conceivable  that  substances  of  very  varied  character 
(as  xylose,  gluconic  acid,  mannite,  glycerol,  alcohol,  tartaric 
acid,  lactic  acid,  propionic  acid,  citric  acid,  glycocoll,  alanin, 
glutaminic  acid)  which  readily  undergo  combustion  in  the  liv- 
ing body,  may  at  times  manifest  an  antiketogenic  power.30 
An  especially  marked  antiketogenic  influence  is  ascribed  by 
J.  Baer  and  L.  Blum  (from  their  observations  in  phoridzin 

COOH 
CH: 

diabetes)  to  glutaric  acid,  CH2   ;  it  is  said  its  antiketogenic 

CH2 
COOH 

influence  is  all  the  more  definite,  the  more  marked  the  sugar 
excretion  and  the  more  severe  the  disturbance  of  metabolism 
which  manifests  itself  in  the  acidosis.  In  severe  acidosis 
and  high  grade  glycosuria  after  phloridzin  administration 
the  authors  mentioned  have  observed  a  complete  disappear- 
ance of  sugar  and  of  oxybutyric  acid,  along  with  marked 
reduction  in  the  nitrogen  elimination.  A  similar  influence  is 
ascribed  also  to  the  homologous  dicarbooxylic  acids  with  five 
to  ten  carbon  atoms  in  their  chains,  the  influence  decreas- 

■*G.  Embden  and  S.  Wirth,  Biochem.  Zeitschr.,  27,  1,  1910. 

30  Cf.  Literature:  A.  Magnus-Levy,  Noorden's  Handb.  d.  Pathol,  d.  Stoffw., 
2d  ed.,  1,  184,  1906;  G.  Satta  (Frankfurt  a.  M.),  Hofmeister's  Beitr.,  6,  376, 
1905;  J.  Bär  and  L.  Blum  (Strassburg) ,  Hofmeister's  Beitr.,  10,  90,  1907; 
11,  101,  1908;  Arch.  f.  exper.  Pathol.,  65,  1,  1911;  O.  Neubauer,  Münchener 
med.  Wochenschr.,  1906,  791. 


444  ACETONE  BODIES 

ing  as  the  number  of  carbon  atoms  increases.  A.  J.  Ringer 
has  very  recently  occasioned  a  great  deal  of  surprise 
by  reporting  that  in  control  experiments,  conducted  under 
direction  of  Graham  Lusk,  he  was  unable  to  confirm  these 
findings,  and  by  attributing  the  above  results  to  fault  in  the 
experimental  technic  of  his  predecessors.31  In  the  author's 
opinion  however,  the  oft-repeated  results  of  Baer  and  Blum, 
assembled  with  so  much  care,  are  not  to  be  put  aside  in  such 
summary  manner;  it  would  seem  rather  to  be  an  objective 
requirement  to  follow  up  the  particular  factors  which  are 
the  ultimate  cause  of  this  contradiction. 

Ammonia  Elimination  and  Acidosis. — As  already  stated 
the  proportion  of  ammonia  in  the  urine  affords  an  approxi- 
mate evaluation  of  the  elimination  of  oxybutyric  acid.  How- 
ever, the  ammonia,  even  if  a  large  quantity  is  excreted,  does 
not,  according  to  C.  von  Noorden,  ordinarily  represent  more 
than  twenty  to  twenty-five  per  cent,  of  the  total  urinary 
nitrogen.  In  a  case  of  diabetic  coma  we  may,  it  is  true,  meet 
with  not  less  than  forty-five  per  cent,  of  the  total  nitrogen 
as  ammonia.32  Yet  it  would  be  a  decided  misuse  of  words  to 
identify,  as  is  often  done,  two  different  phenomena  like  in- 
creased elimination  of  acetone  bodies  and  of  ammonia,  which, 
of  course,  often  run  along  parallel,  under  the  collective  term 
"acidosis."  There  are  conceivable  cases  in  which  an  in- 
creased ammonia  excretion  is  due  to  altogether  different 
causes.  Disturbances  of  the  synthesis  of  urea  in  the  liver 
may  be  such  a  cause,  as  was  pointed  out  above.  According 
to  W.  Schlesinger 33  an  abnormally  increased  fat  cleavage  in 
the  intestine  and  an  abnormally  high  loss  of  calcium  in  the 
fasces,  from  the  formation  of  relatively  insoluble  lime  soaps, 
may  give  rise  to  alkali  impoverishment  and  to  a  compensa- 
tory increase  of  excretion  of  ammonia.     Then,  too,  a  notable 

31  A.  J.  Ringer  (Univ.  of  Pennsylvania),  Jour,  of  Biol.  Chem.,  12,  223,  1912. 

32  C.  von  Noorden,  Handb.  d.  Pathol,  d.  Stoffvv.,  2d  ed.,  2,  82,  1907 ;  cf.  also 
W.  Camerer,  Zeitschr.  f.  Biol.,  U,  22,  1903. 

33  W.  Schlesinger  (Vienna),  Zeitschr.  f.  klin.  Med.,  5Jh  14,  1904. 


INTERRELATION  OF  ACETONE  BODIES  445 

increase  of  the  lower  fatty  acids  in  the  intestine  doubtless 
calls  out  a  lowering  of  the  alkalinity  of  the  body,  as  the  acids 
appear  in  the  fasces  in  a  practically  entirely  neutralized 
condition.34 

Interrelation  of  the  Acetone  Bodies. — This  discussion  of 
the  acetone  body  problem  would  be  incomplete  were  there 
no  attempt  made  to  explain  the  mutual  relations  of  these 
substances. 

Formerly  this  relationship  was  supposed  to  consist  of  a 
transition  of  the  ß-oxybutyric  acid  in  the  economy  into 
diacetic  acid,  which  then  under  normal  conditions  was  sup- 
posed to  undergo  combustion  (without  forming  acetone  by 
cleavage  of  carbonic  acid).  It  was  presumed,  moreover, 
that  in  severe  diabetes  this  transformation  was  so  disturbed 
that  the  oxybutyric  acid  and  diacetic  acid  were  passed  off 
as  excretions. 

This  conception  must  be  modified,  to  be  in  harmony  with 
modern  investigations.  Otto  Neubauer35  proposes  the  fol- 
lowing schema : 

BUTYRIC   ACID  OXYBUTYRIC   ACID 

CH3  CH3 


CH2  CH.OH 


CH2  CHo 

COOH  COOH 


C02  +  H20 


\     ^CHS 
\       I 
\  CO  CHS 

CH2 >    CO 

I  I 

COOH  CH3 

DIACETIC   ACID  ACETONE. 

According  to  this  the  oxybutyric  acid,  but  not  the  aceto- 
acetic  acid,  would  be  a  normal  intermediate  metabolic  prod- 

54  Cf.  also  A.  Schittenhelm  and  A.  Katzenstein  (Göttingen).  Zeitschr.  f. 
exper.  Pathol.,  2,  542,  1906;  L.  F.  Meyer  and  L.  Langstein  (Berlin),  Jahrb.  f. 
Kinderheilk.,  63,  30,  1906. 

35  O.  Neubauer,  27th  Internat.  Kongr.,  Wiesbaden,  1910,  566. 


446  ACETONE  BODIES 

uct.  In  healthy  individuals  the  oxybutyric  acid  would  be 
converted  by  oxidation  into  carbonic  acid  and  water,  the 
diacetic  acid  not  appearing  as  an  intermediary  product.  In 
case  of  interference  with  the  normal  catabolism  of  oxy- 
butyric acid,  however,  a  false  route  would  be  interposed: 
oxidation  into  diacetic  acid,  and  then  formation  of  acetone 
by  splitting  off  carbon  dioxide.  It  may  be  thus  conceived 
why  in  a  healthy  individual  (as  contrasted  with  the  diabetic 
subject)  even  large  quantities  of  oxybutyric  acid  do  not  give 
rise  to  diacetic  acid  production,36  and  why  in  perfusion  ex- 
periments on  the  normal  liver  (in  contrast  to  a  phloridzin 
liver)  the  amounts  of  oxybutyric  acid  decomposed  are  in 
absolute  disproportion  to  the  newly  formed  diacetic  acid.37 
An  example  of  the  saying  that  when  the  proper  time  ar- 
rives for  a  truth  it  falls  like  a  ripe  fruit  from  the  tree  of 
knowledge,  is  to  be  seen  in  the  fact  that  by  chance  E.  Fried- 
mann in  Berlin,  0.  Neubauer  in  Munich,  H.  D.  Dakin  in  New 
York,  and  L.  Blum  in  Strassburg,  all  recognized  at  the  very 
same  time  that  the  passage  of  oxybutyric  acid  into  diacetic 
acid  is  a  reversible  process,  and  that  the  economy  is  not  only 
able  to  oxidize  the  former  into  the  latter,  but  may  in  reverse 
manner  reduce  diacetic  acid  into  oxybutyric  acid : 

CH3.CH(OH).CH2.COOH    K  >    CH3.CO.CH2.COOH.^ 

How  the  /?-oxybutyric  acid  undergoes  combustion  in  the 
normal  body  is  unknown ;  it  might  be  supposed  that  it  breaks 
down  into  acetic  acid : 

CH3  -  CH(OH)  -  CH2  -  COOH  +  0  =  2  CH3.COOH; 
but  it  is  by  no  means  certain  that  it  is  entirely  consumed.     It 
is  not  impossible  that  the  oxybutyric  acid  may  enter  into 

36  L.  Schwarz,  Zeehuyzen,  Araki  and  others. 

37  B.  O.  Przibram  (F.  Kraus's  Clinic),  Zeitschr.  f.  exper.  Pathol.,  10,  1912. 
38 E.  Friedmann  and  Maase  (Berlin),  Münchener  med.  Wochenschr.,  1910, 

No.  34;  Biochem.  Zeitschr.,  21,  474,  1910;  O.  Neubauer,  1.  c;  L.  Blum,  Intern. 
Kongr.,  1910,  Münchener  med.  Wochenschr.,  57,  1910;  H.  D.  Dakin  (New 
York),  Jour,  of  Biol.  Chem.,  8,  97,  1910;  A.  J.  Wakeman  and  H.  D.  Dakin, 
ibid.,  105. 


INTERRELATION  OF  ACETONE  BODIES  447 

further  synthetic  changes.  A  number  of  authorities,  as 
Minkowski  and  von  Noorden,  have  thought  that  it  may  per- 
haps be  looked  upon  as  an  intermediate  link  between  fat  and 
sugar.39  The  statement  has  been  made  above  that  there 
is  at  present  no  convincing  basis  for  Geelmuyden's  view  that 
the  acetone  bodies  should  be  regarded  as  transition  stages  in 
the  supposed  formation  of  sugar  from  fat.  There  are  many 
arguments  against  the  idea  that  oxybutyric  acid  can  be  in 
any  way  concerned  with  the  synthetic  formation  of  fatty 
acids  from  carbohydrates.  Embden,  in  his  last  publications, 
expresses  the  belief  that  the  route  from  sugar  to  the  fatty 
acids  may,  perhaps,  lie  through  lactic  acid,  acetaldehyde  and 
diacetic  acid.  "Acetaldehyde,  as  E.  Friedmann  first  showed, 
in  the  experimentally  perfused  liver  forms  diacetic  acid.  If 
acetaldehyde,  as  would  appear,  is  a  product  of  carbohydrate 
catabolism  which  develops  in  very  large  amounts,  we  may 
perhaps  regard  this  substance,  as  earlier  authors  have  sug- 
gested, as  the  point  of  attack  in  the  synthetic  production  of 
fatty  acids  from  carbohydrates. ' ' 40  Should  this  line  of 
thought  prove  correct  an  interesting  relation  would  be  estab- 
lished between  the  acetone  bodies  with  both  the  anabolism 
and  catabolism  of  the  higher  fatty  acids.  Thus  far,  how- 
ever, the  connection  of  these  substances  with  fat  decomposi- 
tion in  the  economy  constitutes  the  best  based  phase  of  the 
whole  problem. 

The  fact  that  enzymic  catalysers  are  known  to  exist  in 
the  tissues,  which  are  capable  of  oxidizing  oxybutyric  acid 
to  form  diacetic  acid,41  and  of  converting  the  latter  into 
acetone  by  splitting  off  carbon  dioxide,42  is  no  proof  that  this 
is  a  process  which  takes  place  physiologically. 

It  is  impossible  to  say  at  present  what  factors  determine 

39  Cf.  B.  O.  Przibram,  1.  c. 

40  G.  Embden  and  M.  Oppenheimer,  Biochem.  Zeitschr.,  45,  202-203,  1912. 

41  A.  F.  Wakeman  and  H.  D.  Dakin,  Jour,  of  Biol.  Chem.,  6,  373,  1909. 

42 L.  Pollak  (R.  Paltauf's  Instit.,  Vienna),  Hofmeister's  Beitr.  10,  232, 
1907. 


448  ACETONE  BODIES 

whether  the  diacetic  acid  arising  in  metabolism  is  to  be 
excreted  unchanged  or  as  acetone.  According  to  Lüthje43 
a  portion  of  the  diacetic  acid  may  perhaps  be  excreted  by 
the  kidneys  as  an  alkaline  salt,  provided  sufficient  supply  of 
alkali  be  available;  this  portion  otherwise  appearing  as 
acetone. 

Determination  of  Acetone  and  Diacetic  Acid. — In  con- 
clusion a  few  remarks  upon  the  quantitative  determination 
of  the  acetone  bodies  are  desirable.44 

In  the  determination  of  acetone,  precedence  is  still  given 
to  the  long  approved  Messinger-Huppert  method.  This  con- 
sists in  distillation  of  the  acetone  from  the  urine,  transform- 
ing it  into  iodoform  by  means  of  iodide  of  potassium  in  an 
alkaline  solution,  and  determining  by  titration  the  amount 
of  iodine  used  in  the  formation  of  iodoform.  Acetone  can 
also  be  separated  from  the  distillate  by  •  nitrophynylhy- 
drazine  (according  to  Eckenstein  and  Blancksma)  as  a  bright 
yellow  crystalline  sediment,  and  weighed.45  It  may,  too,  be 
precipitated  by  an  alkaline  solution  of  mercuric  cyanide,  the 
acetone-mercurial  precipitate  broken  up  by  acids,  and  the 
mercury  determined  by  titration  (very  like  Vollhard  's  method 
of  determining  silver).46  Finally  the  fixation  of  sodium 
bisulphite  by  acetone  may  be  used  for  iodometric  estimation, 
provided  a  very  long  period  of  reaction  is  given  ;47  while  in 
experiments  of  short  duration  hydrolytic  dissociation  is  so 
marked  that  besides  the  fixed  sulphurous  acid  there  is  always 
present  a  considerable  fraction  in  free  state.48    In  the  de- 

43  H.  J.  Lüthje  (Kiel),  Therap.  d.  Gegenw.,  51,  8,  1910. 

41  Literature  upon  the  Quantitative  Determination  of  the  Acetone  Bodies : 
G.  Embden  and  G.  Schmitz,  Handb.  d.  Biochem.,  3,  906-939,  1910;  E.  Letsche, 
ibid.,  5,  1,  197-199,  1911;  cf.  also  G.  Embden  and  L.  Michaud,  Biochem. 
Zeitschr.,  13,  262,  1908 ;    Hofmeister's  Beitr.,  11,  332,  1908. 

45  S.  Möller  (v.  Leyden's  Clinic),  Zeitschr.  f.  klin.  Med.,  6/f,  207,  1907; 
W.  C.  de  Graaff,  Pharmac.  Weekbl.,  U,  555;  Jahresber.  f.  Tierchem.,  37,  356, 
1907. 

46  H.  Scott  Wilson  (Oxford),  Jour,  of  Physiol.,  Iß,  444,  1911. 

47  A.  Jolles,  Ber.  d.  deutsch,  ehem.  Ges.,  39,  1306,  1906. 

48 J.  Mondschein  (under  direction  of  O.  v.  Fürth),  Biochem.  Zeitschr., 
Iß,  95-97,  1912. 


DETERMINATION  OF  OXYBUTYRIC  ACID  449 

termination  of  acetone,  if  glucose  be  present  in  the  urine, 
special  care  should  be  taken,  because  in  heating  sugar-con- 
taining solutions  substances  of  the  nature  of  ketones  and 
aldehydes  are  easily  produced  which  may  be  confused  some- 
times with  acetone.49 

Separation  of  acetone  and  cliacetic  acid,  as  elaborated  by 
Embden  and  Schliep  50  and  by  Folin,51  is  performed  by  driv- 
ing over  the  preformed  acetone  in  a  given  amount  of  urine 
by  careful  distillation  at  very  low  pressure  and  temperature 
(not  above  35°  C),  or  by  an  air  current,  and  estimating  it. 
Another  portion  of  urine  is  subjected  to  the  Messinger 
method,  after  boiling  with  phosphoric  acid,  the  diacetic  acid 
being  thus  converted  into  acetone;  by  which  measure  the 
total  of  acetone  and  diacetic  acid  is  obtained.  Rowald 52 
recommends  a  combination  of  Embden 's  vacuum  distillation 
with  the  method  of  precipitation  by  nitrophenylhydrazine  as 
the  most  practicable  means  of  separate  determination  of 
acetone  and  diacetic  acid. 

Quantitative  Determination  of  Oxybutyria  Acid. — There 
are  essentially  four  methods  available  for  quantitative  de- 
termination of  oxybutyric  acid :  Polarimetrie  estimation,  con- 
version into  crotonic  acid,  into  diacetic  acid  and  into  acetone. 

The  Polarimetrie  method  worked  out  by  Magnus-Levy, 
depending  upon  the  optical  activity  of  oxybutyric  acid  and 
yielding  excellent  results  when  large  amounts  are  present,  is 
not  reliable  when  one  is  dealing  with  small  quantities,  be- 
cause of  laevogyrating  substances  which  can  be  obtained 
even  from  normal  urine  in  ether  extraction,  and  because  the 
specific  rotating  power  of  ß-oxybutyric  acid  is  not  high.53 

Darmstädter  proposed   a  method  by  which  the   oxy- 

49 Borchhardt  (Wiesbaden),  Hofmeister's  Beitr.,  8,  62,  1906. 

60 L.  Schliep  (Embden's  Lab.),  Centralbl.  f.  Stoff w.,  No.  2,  250,  289,  1907. 

61  0.  Folin,  Jour,  of  Biol.  Chem.,  3,  177,  1907;  J.  S.  Hart,  Jour,  of  Biol. 
Chem.,  k,  473,  1908. 

62  J.  Rowald,  Inaug.  Dissert.,  Giessen,  1908. 

63  Embden  and  Schmitz,  Geelmuyden,  B.  O.  Przibram,  Zeitschr.  f.  exper. 
Pathol.,  10,  279,  1912. 

29 


450  ACETONE  BODIES 

butyric  acid  is  converted  into  crotonic  acid  by  distillation 
with  sulphuric  acid,  with  separation  of  water,  and  the 
crotonic  acid  then  determined  by  alkalimetry.  This  method, 
however,  has  proved  to  be  rather  inexact  in  control  tests  ;54 
but  apparently  excellent  results  are  obtained,  according  to 
Eyffel 55  and  B.  0.  Przibram,56  by  determining  the  crotonic 
acid,  not  by  alkalimetry,  but  by  taking  advantage  of  its 
ability  to  fix  bromine : 

OXYBUTYRIC   ACID  CROTONIC  ACID  BROMINE   ADDITION   PRODUCT 

CH3  CH3  CHj 

CH.OH  CH  CH.Br 

I  >  II >  I 

CH2  CH  CH.Br 

COOH  COOH  COOH. 

The  bromine  is  added  in  excess ;  the  excess  of  bromine, 
on  the  addition  of  potassium  iodide,  sets  free  an  equivalent 
amount  of  iodine  which  is  estimated  by  titration  with  thiosul- 
phate.  It  is  recommended  that  the  urine  be  not  subjected 
to  direct  sulphuric  acid  distillation,  but  that,  saturated  with 
ammonium  sulphate  and  acidulated  with  sulphuric  acid,  it 
be  first  extracted  for  twenty-four  hours  with  ether  in  Lindt's 
apparatus  and  the  ethereal  extract  further  employed. 

A  colorimetric  method  of  estimating  oxybutyric  acid  has 
been  proposed,  depending  upon  transformation  of  oxy- 
butyric acid  into  diacetic  acid  by  hydrogen  peroxide,  and 
subsequent  estimation  of  the  latter  optically  by  the  beautiful 
red  color  which  it  yields  on  addition  of  ferric  chloride.57  In 
view  of  the  instability  of  diacetic  acid,  however,  it  is  impos- 
sible to  restrain  a  feeling  of  distrust  for  this  method. 

An  excellent  mode  of  determination,  however,  is  afforded 
in  Schaff  er  's  method,5S  which  consists  of  heating  to  boiling 
the  fluid  containing  the  oxybutyric  acid,  in  the  presence  of 

"  Embden  and  Schmitz,  B.  O.  Przibram,  1.  c. 

55  Ryffel,  Jour,  of  Physiol.,  82,  Proc.  Physiol.  Soc,  LVI,  May  20,  1905. 

63  0.  F.  Black,  Jour,  of  Biol.  Chem.,  5,  207,  1908. 

07  B.  O.  Przibram,  1.  c. 

88  P.  A.  SchafFer,  Jour,  of  Biol.  Chem.,  5,  211,  1908. 


DETERMINATION  OF  OXYBUTYRIC  ACID  451 

dilute  sulphuric  acid,  and  then  decomposing  it  by  adding 
drop  by  drop  a  solution  of  potassium  bichromate.  The  oxy- 
butyric  acid  undergoes  decomposition  according  to  the  fol- 
lowing formula,  into  diacetic  acid,  then  into  acetone,  carbon 
dioxide  and  water : 


CH3  CH 

.OH  CO 

I 

CH 
COOH 


CH.OH  CO 

I  +  O   =   H,0  +     |  =  H20  +   C02  +  CO 

CH2  CH2 

CH,. 


The  acetone  distilled  over  is  taken  up  in  water  and  the 
proportion  determined  by  Messinger 's  method  with  iodine 
and  thiosulphate.  J.  Mondschein,59  who  worked  out  a 
method  in  the  author's  laboratory  by  which  the  quantitative 
estimation  of  oxybutyric  and  lactic  acids  is  possible  together 
(vide  infra),  was  able  to  fully  satisfy  himself  of  the  delicacy 
of  Schaff  er 's  method. 

So  much  may  be  said  of  the  acetone  bodies  and  their 
physiological  significance. 

50  J.  Mondschein,  1.  e. 


CHAPTER  XIX 

LACTIC   ACID.    FATE   OF  BODY-FOREIGN   SUBSTANCES 
IN  THE  ECONOMY 

LACTIC  ACID 

As  an  addendum  to  the  acetone  bodies  it  seems  desirable 
at  this  place  to  examine  into  the  problem  of  lactic  acid,  which 
is  of  the  greatest  importance  to  the  comprehension  of  the 
metabolic  processes.  This  is  one  of  those  questions  which 
are  always  of  special  stimulative  interest  to  the  writer,  not 
so  much  because  of  the  wealth  of  knowledge  which  comes  im- 
mediately from  them  (for  this  for  the  present  can  satisfy 
only  very  modest  demands)  but  rather  because  of  the  feeling 
that  here  we  are  before  the  entrance  to  a  steep  and  laborious 
mountain  trail  which  may  lead  one,  if  he  be  able  to  surmount 
its  difficulties,  to  a  broad  and  as  yet  unknown  plateau. 

Quantitative  Estimation  of  Lactic  Acid  by  the  Method  of 
Fürth  and  Charnass. — The  reason  that  the  lactic  acid  prob- 
lem has  not  advanced  more  rapidly  is  primarily  due  to  the 
fact  that  it  has  been  only  recently  that  a  successful  method 
of  overcoming  the  difficulties  of  exact  lactic  acid  estimation 
has  been  attained.  The  older  authors  conducted  their  de- 
terminations of  lactic  acid  as  a  rule  by  extracting  it  by 
simply  shaking  it  for  a  time  with  ether  in  a  separatory  fun- 
nel, then  forming  the  relatively  insoluble  zinc  or  lithium 
salt  of  lactic  acid  and  weighing  it.  As  lactic  acid  is  by  no 
means  readily  taken  up  by  ether  from  water,  and  as  quan- 
titative extraction  is  seemingly  possible  only  by  long  con- 
tinued treatment  in  some  such  elaborate  apparatus  as 
Lindt's  rotating  extraction  apparatus,  as,  too,  the  above  men- 
tioned salts  are  not  entirely  insoluble  in  their  mother  fluids, 
and  impurities  can  be  removed  only  by  repeated  crystalliza- 
tion, it  must  be  evident  that  the  older  methods  of  estimating 
lactic  acid  were  attended  by  very  serious  faults  and  that 
452 


QUANTITATIVE  ESTIMATION  OF  LACTIC  ACID    453 

the  results  from  such  methods  seem  extremely  unreliable. 
Boas  had  originally  recommended  that  in  qualitative  de- 
termination of  lactic  acid  (as  in  gastric  juice)  the  fluid  under 
examination  be  distilled  with  manganese  and  sulphuric  acid 
and  the  acetaldehyde,  formed  according  to  the  equation : 

CH3 

I  CH3 

CH.OH  +  0=1  +  C02  +  HjO, 

COH 
COOH 

be  determined  by  transforming  it  into  iodoform  with  an 
alkaline  solution  of  iodine.  E.  Jerusalem  having  shown  in 
the  author's  laboratory  that  oxidation  of  lactic  acid  in  hot 
sulphuric  acid  solution  by  the  addition  of  drop  after  drop 
of  permanganate  solution  may  be  employed  for  the  purpose 
of  quantitative  determination,1  the  author,  in  collaboration 
with  D.  Charnass,2  worked  out  a  reliable  method  based  upon 
this  principle  for  its  quantitative  estimation.  They  were 
able  to  show  that  oxidation  cleavage  of  aldehyde  from  lactic 
acid  occurs  when  certain  experimental  conditions  are  main- 
tained, even  if  not  absolutely  quantitatively,  at  least  with 
such  a  degree  of  uniformity  that  a  quantitative  method  can 
very  well  be  based  upon  this  process  as  a  foundation.  Titri- 
metric  estimation  of  aldehyde  by  the  iodoform  method  gives 
reliable  results  only  when  very  exact  experimental  condi- 
tions are  maintained.  It  is  very  inferior  in  practice  to  the 
iodometric  method  of  Eipper  based  on  the  addition  of 
bisulphite : 

CHj  CH3 

I         +  NaHS03    =      I  /H 
COH  C(-ONa 

\HS03, 

as  the  latter  yields  almost  theoretically  correct  results.3  The 

1E.  Jerusalem  (under  direction  of  0.  v.  Fürth),  Biochem.  Zeitschr.,  12, 
361,  379,  1908;  O.  v.  Fürth,  Emendation  to  article  of  E.  Jerusalem,  ibid.,  2k, 
266,  1910. 

20.  v.  Fürth  and  D.  Charnass,  Biochem.  Zeitschr.,  26,  199,  1910. 

»Cf.  also  W.  Sobolowa  and  J.  Zaleski  (St.  Petersburg),  Zeitschr.  f.  physiol. 
Chem.,  69,  441,  1910. 


454  LACTIC  ACID 

amount  of  aldehyde  obtained  from  lactic  acid  in  the  v.  Fürth 
and  Charnass  tests  averaged  eighty-nine  per  cent,  of  the 
theoretical  value;  and  the  constant  error  is  taken  into  ac- 
count by  introducing  a  correction  factor.  In  Embden's 
laboratory 4  several  improvements  have  recently  been  made 
in  the  method,  which  make  it  satisfy  even  far  reaching  re- 
quirements. The  aldehyde  recovery  of  the  original  method 
particularly  can  be  increased  by  using  a  very  dilute  solution 
of  permanganate  (n/100  instead  of  n/10  solution)  for 
oxidizing  purposes. 

Observations  in  Embden's  laboratory  show  the  need 
which  existed  for  replacing  the  weighing  of  the  zinc  lactate 
by  another  and  better  method.  This  is  done  by  extracting 
the  lactic  acid  for  about  twenty-four  hours  in  the  Lindt 
rotary  apparatus  (which  forces  a  whirl  of  very  fine  ether 
bubbles  through  the  fluid)  and  removing  the  lactic  acid  from 
the  etheral  extract  for  weighing  as  zinc  lactate.  Control  ex- 
periments by  the  author's  method  show  that  in  determina- 
tions of  lactic  acid  from  tissue  extracts  made  by  weighing 
the  lactate  of  zinc,  the  zinc  salts  contain  so  many  impurities 
at  times  that  no  fixed  conclusions  can  be  drawn  as  to  the 
amounts  of  lactic  acid  present  by  mere  weighing.5 

A  source  of  error  until  recently  entirely  overlooked  in 
the  determination  of  lactic  acid  in  tissues  may  arise  from 
the  fixation  of  the  free  lactic  acid  by  the  tissue  proteins. 
J.  Mondschein,0  for  example,  has  determined  in  the  author's 
laboratory  that  the  previously  existing  statements  as  to  the 
amount  of  lactic  acid  in  muscle  are  too  low,  as  about  one- 
third  of  the  lactic  acid  present  (which,  if  the  tissue  is  well 
boiled,  remains  fixed  in  the  coagulum  because  of  combina- 
tions with  proteins)    escapes   estimation.     However,   the 

4G.  Embden,  Handb.  d.  biocbem.  Arbeitsnieth.,  5,  1255-1259,  1912. 
6S.  Oppenheimer  (Embden's  Lab.),  Biochem.  Zeitschr.,  45,  30,  1912. 
6  J.  Mondschein  (under  direction  of  O.  v.  Fürth),  Biochemie.  Zeitschr.,  42, 
105,  1912. 


METHOD  OF  LACTIC  ACID  DETERMINATION      455 

lactic  acid  in  the  extract  obtained  by  boiling  mnscle  can  be 
determined  with  great  accuracy  by  titration  (using  Phenol- 
phthalein as  indicator),  because  all  the  recognizable  lactic 
acid  is  present  in  free  form,  and  the  amount  of  other  acid 
products  is  of  no  practical  importance ;  and  the  fraction  of 
lactic  acid  in  the  proteid  coagulum  can  be  released  for  de- 
termination by  liquefying  the  coagulum  by  heating  with 
caustic  alkali,  the  albuminous  fluid  freed  of  its  protein  by 
addition  of  saturated  salt  solution,  and  finally  the  lactic  acid 
determined  by  the  method  proposed  by  the  author  and 
Charnass  in  the  protein-free  filtrate. 

Determination  of  Lactic  Acid  and  ß-oxybutyric  Acids 
Together. — Recourse  should  also  be  had  to  a  special  method 
for  determination  of  lactic  acid  in  case  fluids  containing  both 
lactic  acid  and  ß-oxybutyric  acids  are  to  be  dealt  with.  In 
separate  portions  the  two  acids  may  be  determined,  respec- 
tively, as  aldehyde  or  acetone  (v.  sup.),  after  oxidation  with 
permanganate  or  with  bichromate  in  a  sulphuric  acid  solu- 
tion. As  in  both  cases,  however,  a  mixture  of  aldehyde  and 
acetone  distills  over,  separation  of  the  two  substances  is 
requisite.  In  estimating  the  lactic  acid  a  modification  is  in- 
troduced, whereby  in  an  aliquot  portion  of  the  distillate  the 
readily  destroyed  aldehyde  is  decomposed  by  boiling  with 
hydrogen  peroxide  and  potassium  hydrate,  the  acetone  re- 
distilled and  titrated  according  to  Eipper.  In  estimating 
the  butyric  acid  the  distillate  (containing  acetone  and  alde- 
hyde) is  freed  of  its  aldehyde  by  boiling  with  hydrogen 
peroxide  and  caustic  potash ;  the  acetone  is  redistilled  and 
determined  by  titration  according  to  Messinger 's  method.7 

Ryjfel's  Method  of  Lactic  Acid  Determination. — Ryffel 
proposed  a  method  of  lactic  acid  determination  which  de- 
pends upon  a  somewhat  different  principle.  In  this  the 
lactic  acid  in  the  urine  is  broken  up  directly  into  acetaldehyde 

7  J.  Mondschein  (under  direction  of  0.  v.  Fürth),  Biochem.  Zeitschr.,  Iß, 
91,  1912. 


456  LACTIC  ACID 

and  formic  acid  by  distillation  with  fifty  per  cent,  sulphuric 
acid : 

CH5 

^HjOH 

I 

COOH 


CH3     +  H 
CHjOH    -    I  I 

I  COH         COOH. 


The  aldehyde  is  then  estimated  colorimetrically  by  the  hand- 
some red  color  which  it  strikes  with  a  rosaniline  solution 
decolorized  with  sulphurous  acid.8 

Postmortem  Formation  of  Lactic  Acid. — We  may  at  this 
point  take  up  again  the  striking  features  of  the  present 
status  of  the  lactic  acid  problem. 

It  should  be  definitely  understood  that  as  sources  of  lactic 
acid  we  must  keep  in  mind  carbohydrates,  proteins,  and,  too, 
a  substance  of  unknown  nature,  which  may  be  characterized, 
following  the  suggestion  of  Embden,  as  lactacidogen.  The 
chemical  relation  with  carbohydrates  may  be  seen  in  the 
very  readily  occurring  decomposition  of  one  molecule  of 
sugar  into  two  molecules  of  lactic  acid :  C6H1206=2  C3H603 ; 
and  for  the  relation  with  proteins  we  may  at  once  refer  to 
the  deamidization  of  alanin:  CH3.CH(NH2).COOH  + 
H20  =  NH3  +  CH3.CH(OH).COOH.  (The  possibility  of 
an  actual  intracorporeal  transformation  of  alanin  into  lactic 
acid  has  been  demonstrated  by  the  experiments  of  Neuberg 
and  Langstein  upon  animals  deprived  of  glycogen.) 

We  may  first  take  up  for  consideration  the  postmortem 
acid  change  of  the  tissues.  The  fact  has  been  known  a  very 
long  time  that  this  is  due  to  formation  of  lactic  acid,  and 
that  the  much  studied  postmortem  production  of  acid  in 
muscle  (Vol.  I  of  this  series,  pp.  145-147,  Chemistry  of  the 
Tissues)  is  nothing  more  than  a  particular  instance  of  a 
process  equally  likely  to  occur  in  all  the  tissues.  This  acid 
change  is  at  present  regarded  as  a  continuation  of  an  intra- 
vital process.  A  great  number  of  investigations  have  been 
devoted  to  the  subject  of  acid  production  in  aseptic  and  anti- 

8  J.  H.  Ryffel,  Jour,  of  Physiol.,  89,  Proc.  Physiol.  Soc,  V,  1909. 


POSTMORTEM  FORMATION  OF  LACTIC  ACID     457 

septic  autolysis,  which  leave  no  doubt  of  the  enzymatic 
nature  of  the  process.  The  acid  met  with  may  be  said  to  be 
8-lactic  acid.  (The  observations  indicating  the  occurrence 
of  inactive  fermentative  lactic  acid  in  autolysis  may  be  fully 
explained,  in  the  writer's  opinion,  by  the  associated  influence 
of  microorganisms.)  9  When  it  is  recalled  that  the  amount 
of  lactic  acid  in  a  specimen  of  tissue  pulp  for  a  time  increases 
until  it  reaches  a  maximum,  and  thereafter  undergoes 
diminution,  and  that  this  decrease  (as  recently  shown  among 
others,  by  Ssobolew,10  in  the  Vienna  Physiological  Insti- 
tute) also  takes  place  under  experimental  conditions  surely 
exclusive  of  bacterial  influence,  we  seem  justified  in  assum- 
ing the  existence  of  enzymes  which  decompose  lactic  acid,  as 
well  as  of  those  which  cause  the  formation  of  this  substance. 
When  a  tissue  juice  contains  an  insufficient  proportion  of 
alkali  lactic  acid  formation  ceases,  apparently  at  a  certain 
degree  of  concentration  of  hydrogen  ions,  by  autoinhibi- 
tion.11  Although  even  earlier  investigations  12  indicated  the 
improbability  of  a  direct  connection  between  the  amount  of 
glycogen  of  a  tissue  (especially  of  muscle)  and  postmortem 
acid  change,  the  author's  pupil,  R.  Türkei,13  recently  de- 
ceased, was  able  to  prove  that  a  liver,  even  if  practically  free 
from  glycogen  and  sugar,  is  capable  of  forming  lactic  acid  in 
the  course  of  autolysis,  and  that,  too,  in  proportions  not  ma- 
terially less  than  is  a  liver  with  normal  carbohydrate  con- 

'Mochizuki  and  Arima,  Kikkoji,  Inouye  and  Kondo;  cf.  Literature:  C. 
Oppenheimer,  Die  Fermente,  3d  ed.,  475,  1909;  E.  Salkowski,  Zeitschr.  f. 
physiol.  Chemie.,  63,  237,  1909;  R.  S.  Frew  (Salkowski'a  Lab.),  ibid.,  60,  15, 
1909;  T.  Saito  and  J.  Yoshikawa,  ibid.,  62,  107,  1909;  T.  Saiki,  Jour,  of  Biol. 
Chem.,  7,  17,  1910;  G.  v.  Stein,  Inaug.  Dissert.,  Berlin,  1911;  Biochem. 
Zeitschr.,  W,  186,  1912:  H.  Youssouf  (Salkowski's  Lab.),  Virchow's  Arch., 
207,  374,  1912. 

10 N.  Ssobolew  (under  direction  of  O.  v.  Fürth),  Biochem.  Zeitschr.,  ^7, 
367,  1912. 

UK.  Kondo  (G.  Embden's  Lab.,  Frankfurt  a.  M.),  Biochem.  Zeitschr.,  ^5, 
63,  1912. 

12 Cf.  Literature:    O.  v.  Fürth,  Ergebn.  d.  Physiol.,  2',  594-600,  1903. 

13  R.  Türkei  (under  direction  of  O.  v.  Fürth),  Biochem.  Zeitschr.,  20,  431, 
1909. 


458  LACTIC  ACID 

tent.  As,  moreover,  introduction  of  alanin  and  inosite 
gave  no  definite  result,  the  conclusions  reached  were  in  con- 
sonance with  the  important  observations  of  Embden  u  with 
carbohydrate-free  expressed  muscle  juices,  and  those  of 
Fletcher15  with  ground  muscle,  that  postmortem  forma- 
tion of  lactic  acid  takes  place  not  at  the  expense  of  carbohy- 
drates, or  of  inosite  or  alanin,  but  at  the  expense  of  some 
unknown  predecessor,  Embden 's  "lactacidogen,"  which  may 
possibly  be  thought  of  as  related  with  the  hypothetic  phos- 
phosarcous  acid  of  Siegfried  (v.  Vol.  I  of  this  series,  p.  148, 
Chemistry  of  the  Tissues). 

The  observations  upon  muscle  autolysis  thus  gave  no 
basis  for  assuming  a  connection  between  lactic  acid  and  the 
carbohydrates.  And  as  no  increase  of  lactic  acid  production 
was  obtained  by  perfusing  the  posterior  extremities  of  dogs 
with  sugar  added  to  the  blood,  Asher  and  Jackson  were  dis- 
posed to  accept  the  idea  that  the  lactic  acid  does  not  arise 
from  carbohydrates  but  from  the  decomposition  of  protein.16 

Origin  of  Lactic  Acid  from  .Sugar. — Much  more  certain 
evidence  of  the  origin  of  lactic  acid  from  carbohydrates  may 
be  met,  however,  in  the  liver  perfusion  experiments  of  Emb- 
den and  his  associates.17  These  indicated  that  in  perfusing 
a  dog's  liver,  free  of  glycogen,  with  bovine  blood  no  lactic 
acid  is  formed  de  novo;  although  in  perfusing  a  liver  rich 
in  glycogen  under  similar  experimental  conditions  there 
could  always  be  observed  a  very  marked  new  formation  of 
S-lactic  acid.  A  result  of  the  same  kind  could  be  obtained, 
although  the  amount  of  acid  was  somewhat  less,  when  glucose 
was  added  to  the  fluid  used  in  perfusing  a  liver  free  of  glyco- 
gen.  Alanin  also  proved  to  be  a  lactic  acid  former.    Embden 

14  G.  Embden  and  F.  Kraus,  26  Kongr.  f.  innere  Med.,  1909,  351;    G.  Emb- 
den, F.  Kalberlah  and  H.  Engel,  Biochem.  Zeitschr.,  45,  58,  1912. 
18  W.  M.  Fletcher  (Cambridge),  Jour,  of  Physiol.,  43,  286,  1911. 

16  L.  Asher  and  H.  C.  Jackson,  Zeitschr.  f.  Biol.,  41,  393,  1901. 

17  G.  Embden  with  M.  Almagia,  Centralbl.  f.  Physiol.,  18,  832,  1905;  v. 
Noorden  and  Embden,  Centralbl.  f.  Stoffw.,  n.  s.,  1,  1,  1906;  G.  Embden  and 
F.  Kraus,  Biochem.  Zeitschr.,  45,  1,  1912. 


ORIGIN  OF  LACTIC  ACID  FROM  SUGAR  459 

came  to  the  conclusion  from  these  results  that  both  the  carbo- 
hydrates and  the  proteins  are  to  be  regarded  as  contributing 
to  the  formation  of  lactic  acid,  the  former,  it  is  true,  ap- 
parently in  much  the  greater  proportion.  This  harmonizes 
closely  with  the  latest  researches  upon  the  nature  of  gly- 
colysis, dealt  with  above  (vide  supra,  p.  338).  Just  as  sugar 
by  the  isolated  influence  of  alkali  is  broken  down  with  ex- 
treme readiness  into  lactic  acid,  we  have  every  reason  for 
assuming  that  physiologically  also  glycolysis  gives  rise  to 
lactic  acid,18  and  that  the  formation  of  lactic  acid  observed  by 
J.  Müller  in  the  surviving  cat's  heart,  for  example,  is  due  to 
direct  cleavage  of  grape  sugar.  Apparently  a  portion  of  the 
lactic  acid  coming  from  sugar  cleavage  in  the  economy  is 
changed  into  ' '  lactacidogen, ' '  which  later  under  certain  con- 
ditions, as  in  postmortem  acid  change,  again  gives  rise  to 
lactic  acid.  "Apparently,"  says  Embden,19  "the  principal 
route  of  carbohydrate  catabolism  in  the  economy  is  by  way  of 
lactic  acid ;  and  in  lactic  acid  the  greater  part  of  the  chem- 
ical energy  which  was  in  the  glucose  is  still  present.  .  .  . 
The  very  fact  that  a  predecessor  of  lactic  acid,  which  is  very 
easily  convertible  into  lactic  acid,  is  at  the  disposal  of  the 
musculature,  permits  one  to  surmise  that  lactic  acid  is  the 
most  substantial  source  of  muscular  power.  ...  It 
should  be  recalled  that  the  older  and  particularly,  too,  re- 
cent authors  regard  it  as  very  probable  that  a  definitely  local 
lactic  acid  production  within  the  muscle  is  concerned  with 
the  relaxation  of  contracted  muscle.  For  the  purpose  of 
rapid  production  of  lactic  acid  this  predecessor  of  lactic  acid, 
which  is  apparently  not  of  acid  nature  or  at  least  less  acid 
than  the  lactic  acid,  may,  perhaps,  have  an  important  part." 
The  author's  ideas  based  upon  his  personal  studies  as  to  the 
role  of  lactic  acid  in  bringing  about  and  relaxing  rigor  mortis 
have  been  discussed  in  a  previous  lecture  (v.  Vol.  I  of  this 
series,  p.  135-147,  Chemistry  of  the  Tissues). 

18  Cf.  J.  H.  Ryffel,  Jour,  of  Physiol.,  kO,  Proc.  Physiol.  Soc,  LI,  1910. 
**G.  Embden,  F.  Kalberlah  and  H.  Engel,  Biochem.  Zeitschr.,  £5,  45,  1912. 


460 


LACTIC  ACID 


Embden's  Schema  of  Sugar  Catabolism  in  the  Living 
Body. — Thanks  to  along  series  of  remarkable  studies  carried 
on  by  Gustav  Embden20  in  the  Frankfurt  Institute  of 
Physiological  Chemistry  in  collaboration  with  a  number  of 
associates,  we  are  able  today  to  frame  very  exact  ideas  as 
to  the  decomposition  of  sugar  into  lactic  acid  and  the  further 
catabolism  of  the  latter.  Embden 21  condenses  these  points 
in  the  following  schema: 


Diacetic  Acid 


a-Glucose 

It 

Glycerol-aldehyde 

It 

3-Lactic  Acid 

U  . 

Racemic  Acid   ^_ 

I 

—  Acetaldehyde    ^_ 

I 

Acetic  Acid. 


""*"  Glycerol 

5- Alanin 
^    Ethyl  Alcohol 


If  we  consider  this  schema  somewhat  more  fully,  in  ac- 
cordance with  it  we  may  suppose  that  physiologically  sugar 
catabolism  would  follow  the  course  below  indicated : 


GLYCEROL- 
ALDEHYDE 


LACTIC 
ACID 


RACEMIC 
ACID 


ACETALDEHYDE 


ACETIC 
ACID 


CH2.OH 

I 

->  CH.OH 

I 
COH 


CH, 

CH.OH 

I 
COOH 


CH, 

I 
CO 

I 

COOH 


CH, 

I 
COH 


CH, 
COOH. 


8UGAR 

CHa.OH 

CH.OH 

CH.OH 

CH.OH 

CH.OH 

COH 

Glycerol-aldehyde  as  an  Intermediate  Product  Between 
Sugar  and  Lactic  Acid. — The  assumption  that  glycerol- 
aldehyde  is  an  intermediate  product  between  glucose  and 

20  G.  Embden  and  associates,  Biochem.  Zeitschr.,  ^5,  1-206,  1912,  and  their 
earlier  studies;    cf.  therein  Literature. 

21  G.  Embden  and  M.  Oppenheimer,  Biochem.  Zeitschr.,  Jt5,  202,  1912. 


SUGAR  AND  LACTIC  ACID  461 

lactic  acid  is  based  on  the  fact  that  it  (in  contrast  to  the 

CH.OH 

isomeric  dioxyaeetone,  CO      ,  which  according  to  Büchner 

CHj.OH 
and  Meisenheimer  is  an  intermediate  product  of  yeast 
fermentation)  has  proved  to  be  a  lactic  acid  producer  of  very 
exceptional  strength.  Embden  suspects  that,  just  as  gly- 
cerolaldehyde  is  an  important  source  for  8-lactic  acid,  di- 
oxyacetone may  be  considered  as  the  chief  source  of  inactive 
fermentative  lactic  acid,  and  expresses  the  idea  that  in  tran- 
sition of  the  glycerolaldehyde  into  lactic  acid 

CH2.OH  CH, 

I  I 

*CH.OH     — >    *  CH.OH 

COH  COOH 

the  middle  carbon  atom  continues  to  retain  its  asymmetrical 
character. 

The  belief  that  glycerol  formation  in  the  economy  also 
proceeds  through  the  intermediate  stage  of  glycerolaldehyde, 
and  that  by  this  route  sugar  may  pass  into  glycerol,  and, 
vice  versa,  glycerol  into  sugar,  is  not  incredible. 

It  may  be  thought,  too,  that  not  only  does  sugar  undergo 
transition  into  lactic  acid,  but  that  the  reverse,  the  transition 
of  lactic  acid  into  sugar,  is  also  possible.  Embden  and  Salo- 
mon 22  have  convinced  themselves  that  lactic  acid  is  a  sugar 
former  in  depancreatized  dogs ;  Mandel  and  Graham  Lusk,23 
in  phloridzinized  animals. 

According  to  Parnas  and  Bär  24  the  route  from  lactic  acid 
to  glucose  leads  through  glyceric  acid  and  glycolaldehyde : 

LACTIC  ACID  GLYCERIC  ACID  GLYCOLALDEHYDE  GLUCOSE 

CH,  CH2OH  CH2.OH    >      C«H120«. 

>-  >■  Condensation 

CH.OH        Oxidation       CH.OH  Oxidation,       COH 

Cleavage  of 

COOH  COOH  H02  and  C02 

n  G.  Embden  and  Salomon,  Hofmeister's  Beitr.,  5,  507,  1904 
23  A.  Mandel  and  G.  Lusk,  Amer.  Jour,  of  Physiol.,  16,  129,  1906. 
M  Cf .  also  J.  Parnas  and  J.  Bär  (Hofmeister's  Lab.,  Strassburg),  Biocbem. 
Zeitschr.,  ^1,  386,  1912. 


462  LACTIC  ACID 

These  authors  also  look  upon  the  route  from  glucose  through 
lactic  acid  to  glyceric  acid  and  glycolaldehyde  as  the  prin- 
cipal mode  of  carbohydrate  catabolism  in  active  metabolism 
of  the  animal  economy. 

Racemic  Acid  as  an  Intermediate  Product. — While  Par- 
nas  and  Bär  are  willing  to  accept  the  formation  of  racemic 
acid  as  at  most  a  by-path  in  the  formation  of  lactic  acid, 
Embden  regards  it  as  the  normal  catabolic  product  of  lactic 
acid  and  as  an  intermediate  product  of  the  transition  of 
alanin  into  lactic  acid  and  vice  versa;  a  view  which  is  in 
harmony  with  the  assumption  of  0.  Neubauer  that  catabol- 
ism of  a-aminoacids  takes  place  through  a-ketonic  acids. 

Paul  Mayer,  25  in  Neuberg's  laboratory,  has  seen  after 
administration  of  racemic  acid  to  rabbits  both  lactic  acid  and 
sugar  in  the  urine.  It  might  well  be  conceived,  therefore, 
that  the  route  from  glucose,  through  lactic  acid,  to  racemic 
acid  may  also  be  traversed  in  the  reverse  way : 

Sugar  <   >  Lactic  Acid  <   >  Racemic  Acid. 

Finally  it  should  be  noted  that  the  route  indicated  in 
Embden 's  schema: 

Glucose — >-Lactic  Acid — ^-Racemic  Acid — >-Acetaldehyde — >-Diacetic  Acid26 

is  possibly  the  one,  too,  which  may  be  taken  by  the  carbo- 
hydrates in  the  synthetic  production  of  higher  fatty  acids 
in  the  body.  Possibly  this  line  of  thought  may  prove  fruitful 
also  in  clearing  up  the  mysterious  processes  of  fat  formation 
in  the  economy. 

Appearance  of  Lactic  Acid  in  the  Urine. — What  do  we 
know,  finally,  of  the  excretion  conditions  of  lactic  acid?  Small 
amounts  are  always  present  in  the  blood.27     In  rabbits,  in- 

86 P.  Mayer  (Neuberg's  Lab.),  Biochem.  Zeitschr.,  40,  441,  1912. 
29 According  to  Neuberg   (Berliner  physiol.  Gesel.,  1912)    racemic  acid  is 
fermented  by  yeast  very  readily  into  acetaldehyde  and  carbonic  acid: 

CH3 
CH,.CO.COOH=C02  +  I 

COH. 
"A.  Fries  (G.  Embden's  Lab.),  Biochem.  Zeitschr.,  85,  368,  1911. 


LACTIC  ACID  IN  URINE  463 

troduced  dextrorotary  lactic  acid,  even  when  administered  in 
large  amounts,  is  almost  completely  consumed,  according  to 
observations  by  J.  Parnas28  in  Hofmeister  's  laboratory. 
Lagvo-rotary  lactic  acid  is  partly  changed,  partly  excreted 
unchanged ;  after  introduction  of  racemic  lactic  acid  an  ex- 
cess of  laevo-rotary  acid  is  eliminated.  From  observations 
made  in  the  Vienna  Pharmacological  Institute  it  seems  that 
the  unconsumed  fraction  of  lactic  acid  is  excreted  partly  as 
such,  partly,  however,  in  the  form  of  other  ether-soluble 
acids.29 

Passage  of  lactic  acid  into  the  urine  is  observed  especially 
after  severe  muscular  efforts,  in  epilepsy  and  eclampsia,  in 
hepatic  affections  (acute  yellow  atrophy,  phosphorus  poi- 
soning, etc.),  in  oxygen  deficiency,  and,  too,  in  geese  after 
extirpation  of  the  liver.30  The  fact  that  uric  acid  contains 
a  tricarbon  nucleus  by  no  means  justifies  the  assumption 
that  the  lactic  acid  excreted  in  the  last  instance  is  a  sub- 
stance which  would  have  been  transformed  into  uric  acid 
under  normal  conditions.31  The  general  impression  is 
given  that  lactic  acid  appears  in  the  urine  in  conditions  in 
which  its  normal  combustion  is  lowered.  However,  it  is 
impossible  as  yet  to  definitely  formulate  how,  where  and 
why  this  is  the  case ;  and  from  appearances  it  is  likely  that 
considerable  time  will  elapse  before  this  is  possible. 

FATE   OF   BODY-FOREIGN  SUBSTANCES   IN   THE  ECONOMY 

Having  in  the  course  of  the  preceding  lectures  attempted 
in  one  way  or  another  to  discuss  in  detail  the  fates  of  the 
most  important  foodstuffs,  proteins,  carbohydrates  and  fats, 
it  may  be  well  to  round  out  our  knowledge  by  endeavoring 

23  J.  Parnas  (F.  Hofmeister's  Lab.,  Strassburg),  Biochem.  Zeitsehr.,  88, 
53,  1912. 

" E.  Neubauer  (Vienna  Pharmacological  Institute),  Arch.  f.  exper.  Pathol., 
61,  387,  1909. 

30  Literature  upon  Lactic  Acid  Excretion:  A.  Ellinger,  Handb.  d.  Biochem., 
8',  651-653,  1910. 

31  Cf.  J.  B.  Leathes,  Ergebn.  d.  Physiol.,  8,  360,  1909. 


464  FATE  OF  BODY-FOREIGN  SUBSTANCES 

to  trace  the  fate  of  a  few  body-foreign  substances  in  the 
intermediate  metabolism.32 

Decomposition  of  Fatty  Acids  and  Aliphatic  Sidechains. 
— In  taking  up  first  the  fatty  acids  and  aliphatic  sidechains 
we  keep  in  direct  connection  with  the  information  gained 
in  the  course  of  the  last  few  lectures  as  to  the  catabolism  of 
fats  and  the  origin  of  the  acetone  bodies.  It  was  pointed  out 
that  the  investigations  of  Knoop  and  Embden  particularly 
have  led  to  the  recognition  that  in  the  disintegration  of  the 
normal  fatty  acids  in  the  animal  body  /^-oxidation  plays 
an  important  part,  and  that  as  a  mode  of  oxidation  we  can 
picture :  R.CH2.CH2.COOB— ►  R.CH(OH).CH2.COOH  — > 
R.CO.CH2.COOH  — >,R.COOH ;  in  which  a  normal  fatty  acid 
passes  first  into  a  ß-oxyacid  by  ß-hydroxylation,  and  this  then 
through  the  corresponding  ß-ketonic  acid  into  an  acid  with 
two  less  carbon  atoms. 

A  long  series  of  careful  studies  conducted  in  the  past  few 
years,  requiring  much  chemical  scientific  knowledge  and 
skill,  especially  by  E.  Friedmann,  F.  Knoop,  H.  D.  Dakin  and 
0.  Neubauer,33  have  been  devoted  to  tracing  out  the  fate  of 
many  phenyl,  halogenphenyl,  furfuryl  and  similar  substitu- 
tions in  fatty  acids,  oxyacids,  ketonic  acids  and  aminoacids  in 
the  course  of  metabolism.  These  studies,  the  details  of 
which  cannot  be  entered  into  here,  have  shown  that  the  above 
mentioned  simple  schema  of  ^-oxidation  cannot  be  accepted 
as  of  general  applicability,  and  that  oxidation  of  fatty  acids 

82  Literature  upon  the  Excretion  of  Body-foreign  Organic  Substances :  A. 
Heffter,  Ergebn.  d.  Physiol.,  4,  184-306,  1905. 

83  F.  Knoop,  Der  Abbau  aromatischer  Fettsäuren  im  Tierkörper,  Freiburg 
i.  B.,  1904;  Hofmeister's  Beitr.,  11,  1908,  and  later  works;  E.  Friedmann, 
Hofmeisters  Beitr.,  11,  151,  1908;  E.  Friedmann  and  C.  Maase,  Bföchem. 
Zeitschr.,  27,  97,  113,  1910;  E.  Friedmann,  ibid.,  27,  119,  1910;  35,  40,  1911; 
Med.  Klinik,  1909,  Nos.  36  and  37,  and  1911,  No.  28;  T.  Sasaki  (E.  Friedmann's 
Lab.),  ibid.,  25,  272,  1910;  H.  D.  Dakin  (New  York),  Jour,  of  Biol.  Chem., 
4-6,  1908-09;  8,  35,  1910;  9,  123,1911;  O.  Neubauer,  with  W.  Gross,  H. 
Fischer,  K.  Fromherz,  Zeitschr.  f.  physiol.  Chem.,  67,  219,  230,  1910;  70,  326, 
1911;  Literature  upon  the  Catabolism  of  Fatty  Acids  and  Aliphatic  Side 
Chains:  O.  Porges,  Ergebn.  d.  Physiol.,  10,  1-46,  1910;  C.  Oppenheimer  and 
Pincussohn,  ibid.,  4',  699-700,  706-709,  1911. 


DECOMPOSITION  OF  FATTY  ACIDS  465 

and  aliphatic  side  chains  takes  place  in  much  more  compli- 
cated ways  which  Friedmann  and  Dakin34  would  outline 
schematically  somewhat  as  follows : 

R.  CH,.  CH2  .  COOH 


/ 

R.CH  =  CH.COOH 

R.CH(OH).   CHa.COOH 


R.CO.CH2.COOH  — >-  R.CO.CH, 


R.COOH  R.COOH. 

If  this  schema  be  applied,  for  illustration,  to  the  indi- 
vidual case  of  phenylpropionic  acid  (CGH5.CH2.CH2.COOH), 
it  will  be  seen  that  it  can  pass  into  either  (by  ß-oxida- 
tion)  phenyl-/?-oxypropionic  acid  (B.CH(OH).CH2.COOH), 
or  into  benzoylacetic  acid  (C6H5.CO.CH2.COOH)  or,  finally, 
into  cinnamic  acid  (C6H5.CH  =  CHjC00H).  The  last  two 
may  then  be  further  catabolized  into  benzoic  acid  (C6H5. 
COOH).  Benzoylacetic  acid  can  by  loss  of  C02  pass  into 
acetophenone  (C6H5.CO.CH3),  or  by  reduction  into  phenyl- 
/S-oxypropionic  acid. 

Transition  of  this  last,  shown  by  the  two  pairs  of  arrows, 
into  benzoylacetic  acid  and  cinnamic  acid  is  fully  analogous 
to  the  previously  mentioned  equation  between  /?-oxybutyric 
acid,  diacetic  acid  and  crotonic  acid : 

CROTONIC   ACID  OXYBUTYRIC    ACID  DIACETIC  ACID 

CH3— CH=CH— COOH  ^  CH3.CH(OH).CH2.COOH  ^CH3.CO.CH2.COOH. 

The  catabolism  of  the  fatty  acids,  therefore,  in  line  with 
this  schema,  is  not  confined  to  simple  oxidation  processes ; 
these  latter  have  associated  with  them  processes  of  reduc- 
tion and  of  water-  and  C02-cleavage.  It  may  be  said  in  pass- 
ing that  the  previously  mentioned  (p.  385)  discoveries  of  E. 
Pick  and  Joannovics  as  to  the  conversion  in  the  liver  of  sa- 

34  E.  Friedmann,  Med.  Klinik,  1911,  No.  28;  H.  D.  Dakin,  Jour,  of  Biol. 
Chem.,  9,  123,  1911. 

30 


466 


FATE  OF  BODY-FOREIGN  SUBSTANCES 


turated  higher  fatty  acids  into  unsaturated  acids  acquire 
special  interest  in  this  connection. 

No  one  knows  how  the  last  phases  of  the  combustion  of 
an  aliphatic  chain  take  place,  and  how  in  particular  acetic 
acid  is  converted.  0.  Porges  believes  that  while  a  small 
fraction  of  acetic  acid  and  its  derivatives  are  oxidized 
through  oxalic  acid,  the  greater  part  is  probably  not  oxidized 
but  undergoes  further  synthetic  elaboration.35  However, 
nothing  definite  is  known  in  this  connection. 

Catabolism  of  the  a-aminoacids. — It  is  generally  held  that 
in  the  decomposition  of  the  physiologically  important  acids 
amidized  in  the  a-position,  these  are  catabolized  through  a 
stage  of  an  a-ketonic  acid  with  C02  cleavage  into  the  acid  of 
the  same  group  with  one  less  carbon  atom  (v.  Vol.  I  of  this 
series,  pp.  49-51,  Chemistry  of  the  Tissues)  in  which  process 
apparently  aldehyde  may  enter  as  an  intermediate  product : 


ALANIN 
CH, 

I 

CH.NH, 

I 
COOH 


RACEMIC   ACID 

CH, 


ACETALDEHYDE 


0 
OOH 


CH, 
COH 


ACETIC  ACID 

CH, 
COOH 


LETJCIN 

CH,    CH, 

V 


CH, 

hi 

COO 


Oxidative 
ÜH.NH2      deamidiza- 


CH3    CH, 

Y 

CH2 

I 
CO 

COOH 


COi  cleav- 
age. 


ISOVALERALDEHYDE 

CH,    CH, 

\/ 

CH 

— >        CH2 
COH 


Oxidation 


ISOVALERIANIC 
ACID 

CH,    CH, 

CI 

I 
>         CH, 


/ 


COOH. 


This  harmonizes  with  the  schema  proposed  by  0.  Neubauer 36 
for  the  catabolism  of  aminoacids  by  yeast  fermentation : 


86  0.  Porges,  Ergebn.  d.  Physiol.,  10,  32,  1910. 

"•O.  Neubauer  and  K.  Fromherz  (F.  v.  Müller's  Clinic,  Munich),  Zeitschr. 
f.  physiol.   Chem.,   70,   348,   1911. 


CATABOLISM  OF  THE  a-AMINOACIDS  467 

AMINO  HYDRATE  OF  KETONIC  ALDEHYDE  ALCOHOL 

ACID  IMINO  ACID  ACID 

R  (oxyacid) 
CH.OH 
/COOH 

R  R  R  /  R  R 

/H          +  O       I    /OH    — NH3     I           — C02   I              +aH        I 
'  >   c;  >    CO       >COH     >-   CH,.OH. 

I     \NH2   Oxidation      I    \NHa  Deamidi-     I  Cleav-  Reduction 

COOH  COOH        zation     COOH   To? 

It  might  well  be  conceived,  too,  that  the  route  from  leucin  to 
isovalerianic  acid  may  pass  through  isoamylamine  and 
isoamylic  alcohol : 37 

LEUCIN  ISOAMYLAMINE  ISOAMYLALCOHOL  ISOVALERIANIC 

ACID 

CH,    CH3  CH3    CH3  CH3    CH3  CH,    CH, 

\/  \y  \/ 


c 


\ 


H  CH  CH  CH 

CH2  CH2  CH2  CH, 

CH.NH2  CH,.NH,  CH2OH  COOH. 

I 
COOH 

In  experiments  of  Friedmann38  (conducted  in  Hofmeis- 
ters' laboratory)  of  the  homologues  of  glycocoll  the  lower 
members  were  better  utilized  by  the  economy  than  the  higher. 

The  catabolism  of  tyrosin  and  Phenylalanin  has  been 
previously  dealt  with  (Vol.  I  of  this  series,  pp.  46-55,  Chem- 
istry of  the  Tissues).  In  this  connection  it  should  be  stated 
that  parahydroxyphenylethylamine  may  undergo  transition 
in  the  economy  into  parahydroxyphenylacetic  acid  :39 


/OH 

/OH 

CsEL 

CH2 

C«ELk 

CH, 

CH2.NH2  COOH. 


37  C.  Oppenheimer  and  Pincussohn,  1.  c,  p.  707;    F.  Sachs   (G.  Embden's 
Lab.,  Frankfurt),  Biochem.  Zeitschr.,  21,  27,  1910. 

38  E.  Friedmann,  Hofmeister's  Beitr.,  11,  151,  1908. 

38  A.  J.  Ewins  and  P.  P.  Laidlow,  Jour,  of  Physiol.,  12,  78,  1910. 


468  FATE  OF  BODY-FOREIGN  SUBSTANCES 

Oxidation  of  Cyclic  Nuclei. — Taking  up  the  question  as  to 
the  extent  an  oxidation  or  disruption  of  cyclic  groups  can 
take  place  in  the  economy,40  there  is  no  doubt  that  these 
cyclic  compounds  frequently  effectively  withstand  even  the 
oxidation  powers  of  the  system,  and  at  times  may  be  either 
excreted  entirely  unchanged  (as  is  the  case  with  phthalic 

/COOH 
acid,  CcH4\mOH'  when  introduced  parenterally  in  rabbits)  41 

or  undergo  merely  hydroxylation.     Thus,  to  take  up  a  few 
examples,  benzol  C6H6  may  pass  into  phenol  C0H5(OH), 

/OH 
aniline  C6H5.NH2  into  paraamidophenol  CjHZ        ,  phenol 

/OH                    /\ 
C6H5(OH)  into  hydrochmon  C«h/       ,  indol    (     \ \  into 

NH 

/\      OH  /VS 

indoxyl  ]  ,  naphthaline  |  into  naphthol,  etc. 


NH 

The  views  as  to  the  movement  of  the  hydroxyls  observed  in 
this  process  of  oxidation  now  and  again  observed,  as  in  the 
transition  of  tyrosin, 

OH 

^H2      ,  into  homogen tisic  acid,  0H\/    , 

CH.NH2  CH2 

I  I 

COOH  COOH 

have  been  stated  in  a  previous  lecture  (Vol.  I  of  this  series, 
pp.  51-52,  Chemistry  of  the  Tissues). 

40  Literature  upon  the  Behavior  of  Benzol  Derivatives  in  the  Economy: 
S.  Fränkel,  Dynamische  Biochemie,  Wiesbaden,  1911,  pp.  53-66. 

41  E.  Przibram,  Arch.  f.  exper.  Pathol.,  51,  372,  1904;    J.  Pohl,  Biochem. 
Zeitschr.,  16,  68,  1909. 


OXIDATION  OF  CYCLIC  NUCLEI 


469 


In  many  cases,  again,  oxidation  takes  place  in  the  nuclear 
ring,  with  change  of  -  CH  =  groups  into  -  CO  -.  Thus,  ac- 
cording to  Fühner,42  quinolin  f  I  passes  into  quinolin- 

\z\y 


N 


qumon, 
CO 


CO 


|c0>  acridin  j  1   into  oxyacridon   [ 

N  N 


N 


As  an  example  of  a  dehydration  of  hydroaromatic  com- 
pounds in  the  body  may  be  mentioned  the  long  known  transi- 
tion of  quinic  acid  (tetraoxycyclohexancarboxylic  acid)  into 
benzoic  acid,  and  the  change  of  hexahydrobenzoic  acid,  as 
observed  by  E.  Friedmann,43  into  benzoic  acid, 


H2C 
H2C 


CH2 

/\ 

.  JcH.CGOH 

\/ 
CH2 


CH 


HC 
HC 


y 

CH. 


./ 


CH 

C.COOH 


Nor  is  there  any  dearth  of  examples  of  nuclear  disruption  in 
the  body.  Here  may  be  classed  the  excellent  observation  of 
Jaffe44  upon  the  occurrence  of  muconic  acid  in  the  urine 
after  administration  by  mouth  of  benzol, 


HC 
HC 


BENZOL 

CH 


MUCONIC  ACID 

CH 


y 

CH 


/ 


CH 
CH 


HC 
HC 


y 

CH. 


COOH 
COOH 


42  H.  Fühner,  Arch.  f.  exper.  Pathol.,  51,  391,  1904;  55,  27,  1906. 

43  E.  Friedmann,  Biochem.  Zeitschr.,  85,  49,  1911. 

44  M.  Jaffe,  Zeitschr.  f.  physiol.  Chem.,  62,  57,  1909. 


470  FATE  OF  BODY-FOREIGN  SUBSTANCES 

The  observation  in  E.  Friedmann  's  laboratory45  of  rup- 
ture of  the  naphthalin  nucleus  when  naphthalanin  and 
naphthyl-racemic  acid  pass  into  benzoic  acid  may  be  noted 
here, 


— CH2.CO.COOH 

COOH. 


It  is  known,  too,  that  tyrosin  and  probably  Phenylalanin 
undergo  advanced  disintegration  in  the  normal  body ;  but  on 
the  other  hand  an  individual  with  alcaptonuria  (v.  Vol.  I  of 
this  series,  p.  47,  et  seq.,  Chemistry  of  the  Tissues)  brings 
this  nucleus  in  hydroxylized  form  in  the  shape  of  homogen- 

tisic  acid,  _J       |  to  the  surface  of  metabolism. 

'  HOL      J— CH2— COOH  ' 


The  fact  that  homogentisic  acid  and  its  mother  substances  in 
the  body  may  undergo  transition  into  aceto-acetic  acid,  or 
into  ß-oxybutyric  acid,46  may  perhaps  be  interpreted  as  indi- 
cating that  homogentisic  acid  is  split  off  as  in  the  schema,47 

C.OH 

,     \  C— CH2— COOH  CO— CH2— COOH 


HC 
HC 


C.OH 


CH 


CH,  ; 


yet,  according  to  what  has  been  previously  said  in  reference 
to  the  formation  of  acetone  bodies,  it  would  appear  at  least 
quite  as  plausible  that  homogentisic  acid  would  break  down 
into  a  bicarbon  complex,  and  /3-oxybutyric  acid  be  formed  by 
way  of  acetaldehyde  and  aldol  synthesis. 

45 F.  Kikkoji  (First  Med.  Clinic,  Berlin),  Biochem.  Zeitschr.,  35,  57,  1911. 

48  G.  Embden,  H.  Salomon  and  F.  Schmidt  (Frankfurt  a.  M.),  Hofmeister's 
Beitr.,  8,  129,  1906;  G.  Embden  and  H.  Engel  (Frankfurt  a.  M.),  Hof- 
meister's Beitr.,  11,  323,  1908;  J.  Bär  and  L.  Blum,  Arch.  f.  exper.  Pathol., 
56,  92,  1907. 

"  T.  Kikkoji,  1.  c,  p.  63. 


DEAMINIZATION  471 

Reduction  Processes  in  the  Economy. — Besides  oxidation 
processes  there  undoubtedly  take  place  reduction  processes 
in  the  body ;  as  examples  may  be  mentioned  the  transition  of 

CC13  CC1, 

chloral,    I       .  into  trichlorethyl  alcohol,    I  •    of  nitro- 

COH  CH2.OH 

/NH2 

benzol,  C6H4.N02,  into  aminophenol,    C^n^tt  »    of  picric 

acid,  C6H4(N03)3(OH),  into  picraminic  acid,  C6H2(N02)2 

/NO, 

(NH2)  (OH),  and  of  nitrobenzaldehyde,  C«H/         ,  into  acetyl- 

/NHCCO.CH,) 
aminobenzoic  acid,  C8HK/-,^^TI  •  (In  the  last  instance  the 

COOH 

reduction  of  the  nitrous  group  into  the  amino  group  takes 
place  with  acetyl  combination  with  the  latter  and  with  oxida- 
tion of  the  aldehyde  group  to  carboxyl.)48  The  "reducing 
ferments ' '  will  be  considered  later. 

Deaminization. — Processes  of  deaminization  are  of  con- 
siderable importance  in  the  economy,  being  indispensable 
to  the  elaboration  of  the  aminoacids  which  go  to  form  the 
protein  molecule.  An  excellent  example  of  intravital  de- 
aminization is  seen  in  the  transition  of  diaminopropionic 

CH2.NH,  CH2.OHM 

acid,    CH.NHs  ,  into  glyceric  acid^  CH.OH  .  The  study  of  the 
COOH  COOH 

elaboration  of  aminoacids  by  low  forms  of  vegetable  life 
affords  very  instructive  analogies  to  deaminization  proc- 
esses in  the  animal  economy.  Reference  has  previously 
been  made  to  the  views  at  present  held  upon  the  action  of 
fermentative  yeasts  on  the  elaboration  of  aminoacids.  By 
mould  fungi  (according  to  the  studies  of  Felix  Ehrlich) 
aminoacids  are  catabolized  typically  following  the  equation : 

48  Literature  upon  Reduction  Processes  in  the  Body :  S.  Fränkel,  Dyna- 
mische Biochemie,  Wiesbaden,  1911,  pp.  71-75;  E.  Meyer  (F.  v.  Müller's 
Clinic,  Munich),  Zeitschr.  f.  physiol.  Chem.,  W,  497,  1905. 

*P.  Mayer    (Salkowski's  Lab.),  Zeitschr.  f.  physiol.  Chem.,  42,  59,  1904. 


472  FATE  OF  BODY-FOREIGN  SUBSTANCES 

B.CH(NH2).COOH  +  H20  =  R.CH(OH).COOH  +  NH3,  it 
being  easy  in  this  way  to  obtain  many  arninoacids,  with  dif- 
ficulty produced  hitherto  in  optically-active  form.  Thus  from 

CH2  CH2 

tyrosin,     Ca   CH.nh2  ,    oxyphenyllactic   acid  CeH*    CH(OH), 

OH       COOH  OH      COOH 

may  be  obtained;  and  from  Phenylalanin  and  tryptophane 
their  corresponding  oxyacids.50 

Synthetic  Formation  of  Arninoacids  in  the  Animal  Body. 
— Our  ideas  about  deaminization  processes  have  been  ma- 
terially extended  by  Knoop  's  discovery  of  a  synthetic  form- 
ation of  arninoacids  in  the  animal  body. 

Knoop öl   in  the  first  place  succeeded,   after  feeding 

phenyl- a-aminobutyric  acid,   I  ,  in  isolat- 

CH2.CH2.CH(NH2).COOH 

C1  TT 

ing  phenyl-  a  -oxybutyric  acid,  I  ,  from  the 

CH2.CH2.CH(OH).COOH 

urine;    but      after    feeding      phenyl- a -ketobutyric    acid, 

CftHj 

,  the  acetyl  compound  of  phenyl-  a  -ammo- 
CH2.CH2.CO.COOH 

butyric  acid.     From  these  observations  he  proposed  the  idea 

that  the  first  phase  of  oxidation  catabolism  of  arninoacids  is 

a  reversible  one : 

AMINOACID  OXTAMINOACID  KETONIC   ACID 

T>  T>  T> 

|/H  +0  I /OH         -NH3  I  +0  R 

C—  NH2  >-  C— NH2  >.  CO        >  I 

I  < I  < I  COOH. 

COOH  — O  COOH  +NH3  COOH 

According  to  this  view  it  would  be  necessary  to  assume 
the  formation  of  a  hypothetical  oxyaminoacid,  arising  pos- 
sibly on  the  one  hand  from  the  aminoacid  by  the  introduction 

60  F.  Ehrlich  and  K.  A.  Jacobsen  (Breslau),  Ber.  d.  deutsch,  ehem.  Ges.,  44, 
888,  1911. 

"F.  Knoop  (Freiburg  i.  B.),  Zeitschr.  f.  physiol.  Chem.,  67,  489,  1910; 
F.  Knoop  and  E.  Kertess,  ibid.,  71,  251,  1911. 


FORMATION  OF  AMINOACIDS 


473 


of  an  atom  of  oxygen,  on  the  other  hand  from  the  ketonic 
acid  by  the  addition  of  a  molecule  of  ammonia.  This  acid 
would,  if  conditions  are  favorable  for  oxidation,  catabolize 
to  ketonic  acid  by  the  cleavage  of  ammonia  and  thereafter  by 
the  introduction  of  an  atom  of  oxygen  to  the  next  lower  acid ; 
if,  however,  conditions  favorable  for  reduction  prevail, 
would  be  reduced  to  aminoacid.  We  know  already,  however, 
that  an  aminoacid  can  be  converted  into  an  oxyacid  by  a 
typical  hydrolytic  deaminizing  process. 

Following  this  line  of  thought  recently  Embden  has  suc- 
ceeded,52 by  experimentally  perfusing  the  liver  of  the  dog 
with  blood  to  which  ammonia  salts  of  various  a-ketonic  acids 
have  been  added,  in  obtaining  their  corresponding  a  -amino- 
acids : 


RACEMATE 

OP 
AMMONIUM 

PHENYLRACE- 

MATE  OF 

AMMONIUM 

a-KETOBUTY- 

RATE  OF 
AMMONIUM 

a-KETO-N-CAPRO- 

ATE  OF 

AMMONIUM 

CH3 

1 

ISO  PROP  YL- 
RACEMATE  OF 
AMMONIUM 
CH3  CH3 

CH3 

1 

CH2 

CH2 

1 

V 

CH 
CH2 

io 

COO(NH4) 

CH3 

1 
CO 

CH2.C6H5 

T 

CO 

CH2 

T 

COO(NH,) 

CH2 
1 
CO 

COO(NH4) 

COO(NH4) 

COO(NH4) 

1 

1 

1 

1 

1 

ALANIN 

PHENYLALANIN 

a-AMINO-BUTY- 
RIC  ACID 

AMINO-N-CAPROIC 
ACID 

CH3 

I 

LEUCIN 

CH3 

| 

CH2 

I 
CH2 

1 

CH3   CH3 

v 

CH 

CH2 

1 

CH3 

CHo.CgHs 

CH2 

CH2 
CH.NH2 

CH.NH2 

CH.NH2 

1 

CH.NH2 
COOH 

CH.NH2 

1 

COOH 

COOH 

COOH 

COOH. 

32  G.  Embden  with  E.  Schmitz  and  K.  Kondo  ( Frankfurt  a.  M. ) ,  Biochem. 
Zeitschr.,  29,  423,  1910;    38,  393,  407,  1912. 


474  FATE  OF  BODY-FOREIGN  SUBSTANCES 

These  findings  are  the  more  significant  as  they  suggest  the 
route  traversed  from  the  non-nitrogenous  products  of  inter- 
mediate metabolism  to  the  ' '  building  stones ' '  of  the  protein 
molecule.  For  instance,  it  may  easily  be  imagined  that 
sugar  is  decomposed  into  lactic  acid  in  the  system,  that  this 
is  then  oxidized  to  racemic  acid  and  that  the  latter  is  changed 
to  alanin  by  taking  up  ammonia : 

SUGAR  LACTIC   ACID  EACEMIC   ACID  ALANIN 

CHj  CH3  CHj 

1                                        I  I 

CsH120,      >■       CH.OH      >■      CO  >•      CH.NH2 

COOH  COOH  COOH. 

It  has  been  actually  shown  in  Embden  's  laboratory  that 
alanin  can  be  found  to  appear  in  a  liver  rich  in  glycogen  (but 
not  in  one  which  is  free  of  glycogen)  in  perfusion  experi- 
ments ;  if  ammonia  be  added  to  the  perfusing  blood  in  the 
experiment  upon  the  glycogen-f  ree  liver,  here,  too,  the  recog- 
nition of  alanin-formation  is  possible.  "This  is  the  first 
time  positive  proof  has  been  obtained  that  in  intermediate 
metabolism  in  the  mammal  carbohydrate  can  be  transformed 
into  an  aminoacid  by  taking  up  nitrogen,  i.e.,  can  be  con- 
verted into  a  characteristic  component  of  the  protein 
molecule. ' ' 53 

Acetylizing  Processes  in  the  Animal  Body. — It  has  been 
shown,  moreover,  that  the  processes  of  anabolism  and 
catabolism  of  the  aminoacids  in  intermediate  metabolism 
are  apparently  closely  connected  with  acetylization  proc- 
esses. Examples  of  the  attachment  of  an  acetic  acid  rest  to 
organic  substances  in  metabolism  have  been  known  for  a 
long  time.  Thus  furfurol  combines  in  the  body  with  acetic 
acid  to  form  furfuracrylic  acid : 54 


-COH  +  CH3.COOH  — >   \~     I  — CH  =  CH— COOH. 

o  o 

"Haimi  Fellner  (G.  Embden's  Lab.),  Biochem.  Zeitschr.,  38,  414,  1912. 
"According  to  Jaffe  and  R.  Cohn. 


ACETYLIZING  PROCESSES  475 

Fixation  of  acetic  acid  to  aminobenzoic-acid 

,NH2  /NH(CO.CHj) 


CgHis"  — ►      CtH4 


X1 


4\:OOH  ^COOH 

has  been  previously  mentioned.  It  seems  too  that  the  mer- 
eapturic  acids  (studied  by  Baumann  and  by  E.  Friedmann), 
which  are  met  in  the  urine  of  dogs  to  which  iodobenzol  or 
bromobenzol  has  been  administered,  owe  their  origin  to  the 
simultaneous  combination  of  cystein  with  halogenbenzol  and 
with  acetic  acid : 55 

BROMO-  ACETIC  BROMOPHENTLMERCAPTURIC 

CYSTEIN  BENZ0L  ACID  ACID 

CH2.SH  CHa-S-CÄBr 

CH.NH2.  +  C«H6Br  +  CH8.COOH >-       CH.NH.(CO.CH3) 

COOH  COOH. 

In  addition,  0.  Neubauer56  and  his  collaborators  have 
obtained  both  in  the  artificially  perfused  liver  of  the  dog, 
and,  too,  under  the  influence  of  fermenting  yeasts  from 

.  -,    C(,H6-CH.COOH      ,       . ., 

phenylammoacetic  acid,  |  (besides  phenylgly- 

NH2 

_  C6H6.CH.COOH* 

oxylic  acid,  C6H5.CO.COOH,  and  amygdalic  acid,        [  J 

.,       C^s-CH.COOH 
acetylphenylammoacetic    acid,  |  .    Knoop,57 

NH(C0.CH3) 
too,   found   that   a   portion   of   phenylaminobutyric   acid, 
C,H6 

.CH2.CH(NH2).COOH 
as  acetyl-derivative.  It  seems,  therefore,  that  a  rather  wide 
distribution  is  to  be  recognized  for  acetylization  in  the  econ- 
omy. Knoop  points  out  a  very  striking  coincidence  between 
this  process  and  the  catabolism  of  aminoacids  from  the  point 
of  view  of  a  transposition  described  by  the  younger  Erlen- 
meyer  and  van  de  Jong,  in  which  two  molecules  of  racemic 

46 E.  Friedmann  (F.  Hofmeister's  Lab.),  Hofmeister's  Beitr.,  4,  486,  1903. 
68  O.  Neubauer,  in  association  with  O.  Warburg  and  K.  Fromherz    (F.  v. 
Miiller's  Clinic,  Munich),  Zeitschr.  f.  physiol.  Chem.,  70,  252,  325,  1911. 
57  F.  Knoop  and  E.  Kertess,  1.  c. 


,  introduced  into  the  system  is  excreted 

CHj.C" 


476  FATE  OF  BODY-FOREIGN  SUBSTANCES 

acid  may,  if  brought  into  contact  at  room  temperature  with 
ammonium  carbonate,  form,  when  heat  is  applied,  a  molecule 
of  acetalanin : 

CH,.CÖ.!cOOH  CH3.CH.COOH 

I     I  I 

NH.jH,;  =  NH  +      COa  +  H20. 

CH3.CO.}COO;H  CH3.CO 

Alkylation — Finally  it  should  be  recalled  {vide  supra, 
p.  132)  that  the  body  is  able  to  bring  about  a  simple  alkyla- 
tion. Thus  after  introduction  of  selenic  or  telluric  acid  into 
the  body,  according  to  F.  Hofmeister,  selenium-methyl  or 
tellurium-methyl  seems  to  appear;    and,  according  to  J. 

,NH2 
^NH, 


Pohl,58  thiourea,  CS^       ,  may  be  partly  changed  into  ethyl 


/C2H5 


sulphide,    s/        .    On  the  other  hand,  the  transformation, 

CH 

Tip    /    ^.    flTT 

observed  by  His,  of  pyriclin,         ||      |      ,  into  methylpyridyl- 

HC  \    /?  CH 

N 
CH 

HCrf  \cH 

ammonium-hydroxide,59  HC\^yCH    ^as  \yeen  definitely  as- 

N 


CH3    OH 
certained.     We  are  apparently  dealing  with  a  methylation 
process,  too,  in  the  change,  described  by  Neuberg,00  of  ethyl 
sulphide  into  the  diethylmethylsulphinium  base, 

C2H5       CH3 

\   / 

s 

/  \ 

C2H5         OH. 

58  J.  Pohl   (Prague),  Arch.  f.  exper.  Pathol.,  51,  341,  1904. 

M  Cf.  E.  Abderhalden,  C.  Brahm  and  A.  Schittenhelm,  Zeitschr.  f .  physiol. 
Chem.,  59,  32,  1909. 

60  C.  Neuberg  and  Grosser,  Deutsche  phys.  Ges.,  1905,  Centralbl.  f.  Physiol., 
19,  316,  1905. 


DETOXIFICATION  BY  SULPHURIC  ACID  477 

Detoxification  by  Sulphuric  Acid  and  Sulphur-containing 
Rests. — There  still  remain  a  group  of  conjugation  processes 
possible  to  the  system  to  be  rapidly  reviewed. 

First  may  be  mentioned  the  conjugation  of  phenols  with 
sulphuric  acid,  discovered  by  Baumann,  which  follows  the 

/K 
schema :  c«H6.OH  +  khso4  -  so/         +  H2o  ;  which  is  applicable 

C*H6 

also  to  dioxyphenol,  trioxyphenol,  halogen-phenols,  nitro- 
phenols,  aminophenols,  cresols,  thymols,  many  substitution 
benzoic  acids,  etc.  In  the  combination  of  sulphuric  acid 
(doubtless  originating  principally  from  oxidized  protein-sul- 
phur) with  phenols  we  undoubtedly  possess  a  method  of 
detoxifying.  After  Marfori  had  discovered  that  intraven- 
ous injection  of  ammonium  sulphate  is  capable  of  detoxify- 
ing a  certain  amount  of  phenol,  it  was  shown  from  a  study  in 
F.  Hofmeister 's  laboratory61  that  the  sulphates  are  decid- 
edly less  efficient  as  detoxifying  agents  than  the  salts  of  sul- 
phurous acid.  The  most  efficient  antidote  for  phenol  poison- 
ing is  apparently,  however,  the  salts  of  persulphuric  acid,62 
II2S208.  Babbits  which  have  received  a  subcutaneous  injec- 
tion of  "persodin"  (a  mixture  of  sodium-  and  ammonium- 
persulphate)  can  withstand  far  more  than  the  maximal  dose 
of  phenol,  sometimes  without  manifesting  the  least  symp- 
toms of  poisoning. 

An  interesting  antitoxic  process  may  be  seen,  too,  in  the 
combination  of  hydrocyanic  acid  and  nitriles  to  form  sulpho- 
cyanides  (KCN  +  S  =  KCNS)  and  the  hastening  of  this 
synthesis  by  the  introduction  of  thiosulphates,  discovered  by 
Sigmund  Lang  in  F.  Hofmeister 's  laboratory.  In  spite  of 
the  rapid  action  of  hydrocyanic  acid  several  times  the  lethal 
dosage  may  be  robbed  of  its  effect  by  supplementary  intra- 
venous exhibition  of  the  thiosulphate.63 

61  S.  Tauber  (F.  Hofmeister's  Lab.),  Arch.  f.  exper.  Pathol.,  36,  196,  1895. 
°-G.  Bufalini,  Arch.  ital.  de  Biol.,  40,  131,  1904. 

88 S.  Lang  (F.  Hofmeister's  Lab.,  Prague),  Arch.  f.  exper.  Pathol.,  36,  75, 
1894. 


478  FATE  OF  BODY-FOREIGN  SUBSTANCES 

According  to  L.  Lewin64  the  poisonous  condensation 
products  of  acetone,  mesityl  oxide  and  phorone,  in  the  body 
enter  into  combination  with  sulphhydryl  and  are  excreted  in 
the  urine  as  thioketones. 

Conjugation  with  Glycocoll  and  Ornithin. — The  conjuga- 
tion of  benzoic  acid  and  its  homologues  with  glycocoll  will  not 
be  dealt  with  here  any  further,  as  hippuric  acid  has  already 
been  considered.  It  is  well  known  that  in  the  economy  all 
substances  which  are  catabolized  to  benzoic  acid  lend  them- 
selves to  synthesis  of  hippuric  acid.  A  number  of  related 
acids,  too,  as  oxy-,  nitro-,  halogen-benzoic  acids,  toluic  acid, 

HCn n  CH 

phenylacetic  acid,  and  too  pyromucic  acid,  HC\^/C.COOH, 

O 
unite  with  glycocoll  according  to  the  equation :  R.COOH  -f 
NH2.CH2.COOH  =  R.CO  -  NH.CH2.COOH  +  H20.  In  the 
economy  of  birds  benzoic  acid  (as  discovered  by  Jaffe),  in- 
stead of  uniting  with  glycocoll,  combines  with  another  pro- 
tein derivative,  Ornithin  (Vol.  I  of  this  series,  p.  10,  Chem- 
istry of  the  Tissues)  to  form  ornithuric  acid: 

ORNITHIN  ORNITHURIC   ACID 

CH2.NH2  CH2.NH(CO.C6H6) 

CH2  CH2 

COOH.C^  I 

CH2  +  >      CH2 

COOH.CcH5  | 

CH.NH2  CH.NH.(CO.C6H6) 

COOH  COOH. 

In  the  avian  economy  pyromucic  acid  and  phenylacetic 
acid,  C6H5  -  CH2.COOH,  may  also  enter  into  an  analogous 
synthesis.65 

J]  r  amino  acids. — There  are  quite  a  large  number  of  state- 
ments in  literature  that  aminoacids  in  the  intermediate 

ML.  Lewin  (Berlin),  Arch.  f.  exper.  Pathol.,  56,  346,  1907. 
06 G.  Totani,  J.  Yoshikawa   (Kyoto),  Zeitschr.  f.  physiol.  Chem.,  6*8,  75, 
1910. 


STEREOISOMERIC  SUBSTANCES  479 

metabolism  supposedly  unite  with  urea  rests.    For  example, 

taurin,  C2H,/     2    ,  according  to  Salkowski  appears  as  tauro- 
xHSO, 

/NH(CO.NH2) 
carbammic  acid,  CjlL/  .  Analogous  statements  are 

\HSOa 

made  of  sulphanilic  acid,  ethylamine,  sarcosin,  tyrosin  and 
Phenylalanin.  However,  from  the  observations  of  Dakin 
upon  tyrosinhydantoin  (Vol.  I  of  this  series,  pp.  16  and  47, 
Chemistry  of  the  Tissues)  and  those  of  Weiland  66  it  appears 
that  not  only  on  boiling  a  urine  after  the  addition  of  an 
aminoacid,  but  on  merely  steaming  it  over  a  water  bath,  or 
even  on  concentrating  a  neutral  aqueous  solution  containing 
urea  and  an  aminoacid  at  a  temperature  of  the  water  bath 
not  above  45°  C.  uraminoacids  are  formed.  "We  are  not  at 
present  in  position  to  make  any  assertions  as  to  the  physio- 
logical significance  of  these  acids.  It  is  quite  possible  that 
they  are  altogether  artificial  products  of  extracorporeal  de- 
velopment (vide  supra,  p.  98). 

Combinations  of  glycuronic  acid  will  not  be  dealt  with 
here,  as  they  have  been  considered  previously. 

Behavior  of  Stereoisomeric  Substances  in  the  Body. — 
These  considerations  of  the  behavior  of  body-foreign  sub- 
stances in  intermediate  metabolism  may  be  concluded  by 
directing  attention  to  the  importance  of  the  stereochemic 
configuration  of  such  substances  from  this  point  of  view. 

The  recognition  of  this  significance  goes  back  to  the 
classical  studies  of  Pasteur  upon  the  influence  of  moulds 
upon  paratartaric  acid  and  those  of  Emil  Fischer  upon  the 
variations  in  the  behavior  of  stereoisomeric  methyl glu- 
cosides  toward  invertin  and  emulsin.  Since  then  a  number 
of  other  comparable  observations  have  been  collected.  For 
example,  studies  upon  asymmetric  cleavage  of  racemic  man- 
delic  acid  methylester,  and  brominated  stearic  acid  glyceride 


MW.  Weiland   (G.  Embden's  Lab.,  Frankfurt  a.  M.),  Biochem.  Zeitschr., 
38,  385,  1912. 


480  FATE  OF  BODY-FOREIGN  SUBSTANCES 

by  lipases07  may  be  classed  here.  Observations  upon  the 
behavior  of  stereoisomers  substances  in  metabolism  have 
been  made  in  case  of  tartaric  acids,08  arabinoses,69,  man- 
noses,70  methylglucosides,71  and  monoaminoacids.72  Par- 
ticularly in  the  case  of  these  last  (as  leucin,  tyrosin,  aspara- 
ginic acid  and  glutaminic  acid)  the  important  point  was  de- 
veloped that  after  introduction  of  these  racemic  compounds 
the  particular  components  which  occur  naturally  in  animal 
protein  readily  underwent  combustion,  while  the  body- 
foreign  components  almost  completely  passed  out  into  the 
urine  of  the  experiment  animal.  Even  the  two  stereoiso- 
meric  methylglucosides  behave  very  differently  in  the  body ; 
and  the  same  is  true  of  isomeric  forms  of  sugar  (it  may  be 
recalled  how  much  more  readily  glucose  is  assimilated  than 
galactose) .  On  the  other  hand,  there  is  no  apparent  differ- 
ence between  8-  and  A-tartaric  acid ;  in  both  cases  racemic 
acid  is  eliminated  in  the  urine  in  unchanged,  inactive  form. 
That  the  system  is  also  able  to  bring  about  changes  in  stereo- 
chemic  configuration  is  evidenced  by  the  conversion  of  laevu- 
lose  into  dextrose  by  the  diabetic  subject,  and  by  the  trans- 
formation of  dextrose  into  galactose  in  the  mammary  gland. 
The  name  " stereokinases"  has  been  proposed  for  the  hypo- 
thetical ferments  supposed  to  bring  such  conversions  about. 
Here,  then,  is  the  end  of  today's  discussion;  and  this  is 
probably  well,  as  the  author  cannot  but  fear  that  the  concen- 
tration of  so  many  formulae  and  dry  chemical  facts  in  such 
brief  outline  must  decidedly  test  his  hearer's  patience.  It  is 
indeed  a  rigid  and  peculiar  material  with  which  this  lecture 
has  had  to  deal,  and  yet  it  is  well  adapted  to  be  shaped  into 
beautiful  plastic  forms  by  the  hands  of  one  who  applies  him- 

67  Dakin,  Neuberg  and  Rosenberg. 

68Brion    (Hofmeister's  Lab.),  Zeitschr.  f.  physiol.  Chem.,  25,  282,  1898; 
Neuberg  and  Saneyoshi,  Biochem.  Zeitschr.,  36,  32,  1911. 

69  C.  Neuberg  and  Wohlgemuth,  Zeitschr.  f.  physiol.  Chem.,  35,  41,  1902. 
1,0  C.  Neuberg  and  P.  Mayer,  Zeitschr.  f .  physiol.  Chem.,  37,  530,  1903. 
n  S.  Lang,  Zeitschr.  f.  klin.  Med.,  55,  1904. 
72  J.  Wohlgemuth,  Ber.  d.  deutsch,  chem.  Ges.,  38,  2064,  1905. 


STEREOISOMERIC  SUBSTANCES  481 

self  with  the  fire  of  true  zeal  for  research.  But  in  this  sculp- 
tor's studio  there  is  need  of  dextrous,  trained  and  diligent 
hands.  The  crowd  of  tyros  in  our  science,  who  it  is  true  are 
making  biochemical  investigations,  but  who  are  not  willing  to 
learn  chemistry,  invariably  keep  away  with  proper  awe  from 
this  workshop,  through  whose  window  flows  a  broad  stream 
of  bright  light  and  in  which  no  lack  of  mental  clarity  and  con- 
fusion are  tolerated.  But  within  the  confines  of  biochem- 
istry there  still  remain  plenty  of  broad  stretches  of  the 
primaeval  forest  where  they  are  entirely  safe  from  this  light, 
where  they  may  meddle  about  undisturbed  in  the  construction 
of  their  papers  upon  subjects  of  temporary  popularity. 


31 


CHAPTER  XX 

NUTRITIONAL  REQUIREMENTS.  FASTING.  PARENTERAL 

NUTRITION 

NUTRITIONAL  REQUIREMENTS 

The  streams  of  nutritive  material  which  are  poured  into 
the  body  have  been  followed  from  the  very  start,  not  with- 
out interruption  to  their  exit,  but  up  to  the  point  where 
they  disappear  in  intermediate  metabolism,  somewhat  like 
waterways  whose  courses  are  suddenly  interrupted  and  lost 
in  the  depths  of  a  labyrinth  of  underground  caves  and  pas- 
sages. At  this  time  it  is  desirable  to  deal  more  fully  not  so 
much  with  the  individual  types  of  food  as  such,  but  rather  in 
a  sense  with  their  effects.  The  present  lecture,  therefore, 
may  properly  be  devoted  to  the  problems  of  nutritional  re- 
quirement, of  inanition,  and  of  restricted  diet.  We  enter 
here  directly  into  a  field  of  study  looked  upon  by  the  older 
physiologists,  so  to  say,  as  the  science  Kax  £|o^v  of  me- 
tabolism. 

Amount  of  Food. — In  calculating  the  normal  nutritional 
requirements  of  an  individual,  for  a  long  time  "Voit's 
dietetic  allowance"  was  used  as  a  basis.  According  to  this 
118  grams  of  protein,  56  grams  of  fat  and  500  grams  of 
carbohydrate  were  regarded  as  the  proper  requirement  of  a 
healthy  human  being  of  about  seventy  kilograms  weight. 
Taking  Rubner's  standard  figures,  according  to  which  one 
gram  of  protein  yields  4.1  calories,  one  gram  of  either  starch, 
glycogen  or  sugar  4.1  calories,  but  one  gram  of  fat  9.3 
calories,  the  total  calory  requirement  foots  up  in  round  num- 
bers three  thousand  calories.  A  long  list  of  studies,  among 
which  may  be  especially  mentioned  those  of  Rubner,  Zuntz, 
Tiger stedt,  Atwater  and  Benedict,  and  Chittenden,1  have 

1  Literature  upon  the  Amount  of  Normal  Food  Requirement:  A.  Magnus- 
Levy,  v.  Noorden's  Handb.  d.  Pathol,  d.  Stoffw.,  2d  ed.,  1,  319-330,  1906; 
0.  Cohnheim,  Physiologie  der  Verdauung  und  Ernährung,  pp.  400-460,   1908. 

482 


METABOLIC  MINIMUM  483 

proved  that  the  idea  of  a  "normal  dietary  allowance"  is  de- 
cidedly misleading,  as  the  amount  of  food  which  a  man  needs 
depends  primarily  upon  the  amount  of  muscular  labor  which 
he  has  to  perform.2  Eubner,  for  instance,  divides  his  human 
observation  material  into  four  classes  according  to  the  type 
of  occupation.  To  the  first  class  belong  persons  with  seden- 
tary occupation  (as  brokers,  the  learned  professions,  mer- 
chants, writers,  textile  workers  and  those  who  attend 
machines) ;  such  individuals  require  about  2400  calories. 
To  the  second  group  he  refers  workers  who  either  work 
standing,  or  engage  in  rather  severe  labor  in  sitting  posi- 
tion; these  need  about  3000  calories.  The  third  class  in- 
cludes individuals  whose  labor  demands  more  physical 
strength  (masons,  smiths,  soldiers  in  forced  marches) ;  these 
requiring  accordingly  a  larger  amount  of  food,  about  3400 
calories.  In  the  fourth  class  finally,  individuals  are  placed 
who  are  required  to  perform  especially  heavy  labor  (as 
farmers,  porters  and  persons  who  undertake  heavy  athletic 
feats) ;  in  these  a  calory  requirement  of  from  4000  to  5000 
commonly  is  met.  Even  this  does  not  cover  the  extreme 
demands.  Atwater  has  met  American  woodsmen  who  easily 
required  7000  to  8000  calories ;  and  there  is  record  of  a  man 
who  rode  a  bicycle  for  sixteen  hours  with  the  imposing 
record  of  9000  calories. 

Metabolic  Minimum. — "What  is  the  metabolic  minimum 
for  man?  Recent  studies  by  Zuntz  and  Tigerstedt3  show 
the  metabolic  minimum  of  the  adult  individual  as  about  one 
calory  pro  kilogram  per  hour.  This  would  mean  about  1700 
calories  for  an  individual  of  seventy  kilograms  weight.  This 
estimate  tallies  fairly  with  the  direct  results  of  respiration 
studies  conducted  by  Sonden  and  Tigerstedt  upon  indi- 
viduals in  sound  sleep,  and  by  Zuntz  and  Lehmann  upon 

2  Cf .  also  A.  Slosse  and  E.  Waxweiler  ( Instit.  Solvay,  Brussels ;  Travaux 
de  l'lnstit.  de  Soeiol.).  Observations  upon  the  nutrition  of  more  than  1000 
Belgian  laborers. 

3R.  Tigerstedt  (Helsingfors),  Skandin.  Arch.  f.  Physiol.,  23,  302,  1910; 
E.  Koch  (Tigerstedt's  Lab.),  ibid.,  25,  315,  1911. 


484  NUTRITIONAL  REQUIREMENTS 

professional  f asters.  Among  bedridden  inmates  of  asylums 
for  the  aged  and  of  insane  asylums  a  calory  requirement  be- 
low 2000  has  often  been  observed,  and  individual  cases  have 
shown  1400  and  less.4  The  really  small  significance  of  such 
figures  may  perhaps  be  appreciated  by  stating  that  this  cor- 
responds, according  to  O.  Cohnheim's  estimation,  to  only 
one  liter  of  milk,  eight  lumps  of  sugar  and  four  wheat-rolls 
a  day. 

Protein  Minimum. — A  question,  which  because  of  its 
economic  and  hygienic  importance  has  aroused  considerable 
discussion,  is — what  is  the  smallest  amount  of  protein  with 
which  a  normal  person  can  actually  get  along?  The  dis- 
tinguished American  physiologist,  Chittenden,  has  endeav- 
ored in  an  extensive  series  of  experiments  to  prove  that 
Voit's  diet,  with  its  118  grams  of  protein  and  3000  calories, 
is  much  too  high;  and  that  a  healthy  human  being  can  get 
on  with  much  less.  From  Chittenden's  experiments,  which 
were  performed  on  educated  persons,  volunteers  of  the 
military  sanitary  service  and  on  trained  student  athletes,  the 
results  would  show,  to  the  author's  mind,  a  requirement  of 
from  1900  to  2500  calories,  about  0.10  to  0.12  protein  nitrogen 
to  the  kilogram  of  body  weight  (i.e.,  43  to  53  grams  of  protein 
for  a  body  weight  of  70  kilograms)  to  be  satisfactory.  Chit- 
tenden came  to  the  conclusion  that,  without  necessarily  rais- 
ing the  consumption  of  non-nitrogenous  foods,  it  is  possible 
to  maintain  nitrogen  equilibrium  by  amounts  of  protein  fully 
fifty  per  cent,  less  than  usually  considered  necessary.5 
O.  Cohnheim  calls  attention  to  the  point  that  in  case  of  many 
foodstuffs  relatively  low  in  nitrogen,  particularly  legumes 
and  bread,  utilization  is  distinctly  poorer  than  for  substances 
commonly  employed  in  metabolic  studies,  and  that  of  the  118 
grams  of  crude  protein  of  Voit's  meal  actually  only  about 
100  grams  are  to  be  regarded  as  digestible.  The  difference 
between  this  latter  and  Chittenden's  results  is  therefore  by 

4  Cf.  the  instructive  collection  of  data  by  O.  Cöhnheim,  1.  c. 
8  Cf.  L.  B.  Mendel,  Ergebn.  d.  Physiol.,  11,  499,  1911. 


PROTEIN  MINIMUM  485 

no  means  as  great  as  would  appear  at  first  glance.  How- 
ever, the  exact  proof  that  an  individual  can  increase  his 
bodily  strength  on  a  moderately  restricted  diet  is  a  matter  of 
lasting  practical  value.  "'The  laudation  of  temperance, ' ' 
says  Magnus-Levy,  "is  sounded  in  Chittenden's  book,  it  is 
true,  less  philosophically  and  aesthetically  than  in  the  pages 
of  a  Ludovico  Cornaro  and  a  Hufeland,  but  certainly  with  no 
less  enthusiasm  and  impressiveness.  ...  If  Chitten- 
den's followers  feel  so  much  better  in  their  new  mode  of  life 
than  formerly,  there  should  be  considered  many  other  fac- 
tors besides  the  reduction  of  protein  in  their  diet  in  explana- 
tion. The  great  regularity  of  their  plan  of  living,  perhaps 
the  different  distribution  of  their  hours  of  eating,  the  almost 
complete  abstention  from  alcohol,  condiments  and  other  irri- 
tative agents,  must  also  be  considered.  .  .  .  Special  promi- 
nence is  due,  too,  to  the  return  to  the  simple  life,  or  as  it  is 
often  spoken  of,  'back  to  nature,'  in  bringing  about  what 
is  almost  a  new  birth  to  Chittenden  and  some  of  his  young 
men.  Vegetarianism,  natural  methods  of  treatment  and 
other  modes  of  nonscientific  therapy  are  indebted  to  them, 
too,  for  their  actual  and  apparent  results."  6 

For  the  other  points  upon  the  theories  of  protein  metab- 
olism and  the  questions  of  protein  minimum  and  protein 
requirement  it  seems  best  to  make  reference  to  the  recent 
clear  and  well  directed  monographs  by  W.  Caspari 7  and  the 
American  physiologist,  Lafayette  B.  Mendel.8  In  these 
publications  there  may  be  found  full  presentations  of  the 
views  held  upon  this  difficult  subject  by  the  authors  and  other 
experts  in  this  field.  These  are  matters  which  to-day  cannot 
be  put  aside  with  a  brief  statement  without  sinning  against 
the  law  of  objectivity.    A  glance  at  Caspari 's  reference  list, 

6  A.  Magnus-Levy,  1.  c,  pp.  326-330. 

'  W.  Caspari,  Handb.  d.  Biochem.,  k ',  722-825,  1911. 

8L.  B.  Mendel  (New  Haven),  Ergebn.  d.  Physiol.,  11,  418-525,  1911;  cf. 
also  K.  Thomas,  Arch.  f.  Anat.  u.  Physiol.,  1910,  Spplbd.,  249,  1911;  M.  Rubner, 
ibid.,  1911,  39-61,  67. 


486  NUTRITIONAL  REQUIREMENTS 

which  contains  more  than  five  hundred  papers,  will  show  the 
propriety  of  so  doing. 

RelationBetweenProtein  Requirement  and  Total  Energy 
Requirement. — How  large  a  part  of  the  energy  requirement 
must  be  furnished  the  economy  in  the  form  of  protein1? 
That  depends  entirely  upon  the  kind  of  nutrition.  Thus 
F.  Siegert 9  found  that  a  fairly  favorable  nutrition  for  the 
growing  child  can  be  attained  if  the  protein  calories  repre- 
sent nine  or  ten  per  cent,  of  the  quantity  of  food  appropriate 
to  the  subject.  In  an  investigation  made  in  Tigerstedt's 
laboratory  10  the  result  indicated  that  of  the  4000  calories  of 
the  food  of  a  Finnish  farmer  or  of  students,  about  15  per 
cent,  are  ingested  in  the  form  of  protein.  Rubner  found 
that  a  physician,  whose  energy  requirement  he  had  con- 
trolled, ordinarily  covered  twenty  per  cent,  with  protein ;  in 
a  Bavarian  woodsman,  however,  only  eight  to  nine  per  cent. 
It  might,  of  course,  be  that  accidentally  both  the  physician 
and  the  woodsman  were  using  the  same  daily  amount  of 
about  one  hundred  grams  of  protein,  but  while  the  physician 
had  an  energy  requirement  of  about  2400  calories,  the  woods- 
man was  by  chance  using  twice  this  amount.  Persons  who 
do  but  little  muscular  work  must,  of  course,  ingest  the  same 
protein  proportion  in  a  smaller  general  quantity  of  food. 
The  amount  of  protein  in  human  diet  is,  as  O.  Cohnheim 
believes,11  nearly  the  same  in  all  peoples  who  have  been 
studied,  Germans,  Scandinavians,  Italians,  Transylvanians, 
Americans,  Japanese  and  Malays.  Independently  of  race, 
climate  and  occupation  the  figures  for  crude  protein  are  said 
to  be  everywhere  from  100  to  130  grams,  for  pure  protein 

'  F.  Siegert  (Cologne),  Arch.  f.  exper.  Pathol.,  S'chmiedeberg  Festschr., 
489,  1908;  cf.  statements  as  to  energy  determinations  of  nutritional  require- 
men  in  the  infant,  by  O.  and  W.  Heubner,  Jahrb.  f.  Kinderheilk.,  ?',?,  121,  1910; 
A.  Schlossmann  and  H.  Murschhauser  (Düsseldorf),  Biochem.  Zeitschr.,  26, 
14,  1910. 

10  S.  Sundström  (Tigerstedt's  Lab.,  Helsingfors),  Dissert.,  Helsingfors, 
1908,  Skandin.  Arch.  f.  Physiol.,  19,  78,  1907. 

"■  O.  Cohnheim,  1.  c,  p.  452,  et  seq. 


PROTEIN  AND  ENERGY  REQUIREMENTS  487 

90  to  120  grams.  It  may  be  added  that  OsMma,12  in  an  in- 
teresting but  little  known  paper  upon  Japanese  diet,  con- 
cludes that  it  is  apparently  fair  to  say  that  the  amount  of 
protein  "  in  the  food  of  those  classes  who  live  mainly  on 
vegetable  material  (and  these  constitute  a  large  part  of  the 
population)  is  not  far  from  60  grams  daily. ' '  This  would  be 
less,  even  if  wTe  take  in  consideration  the  much  smaller 
average  weight  of  the  Japanese,  than  the  above  figures  re- 
garded as  standard  for  an  individual  of  seventy  kilograms 
average  weight.  Doubtless  Cohnheim  was  entirely  correct  in 
suggesting  that  Italian  laborers  and  Chinese  coolies  do  not 
live  on  maize,  rice  and  bread  primarily  because  they  have  any 
special  freedom  from  requirements  or  because  a  hot  climate 
in  itself  produces  a  lessened  requirement  for  food  (accord- 
ing to  Hans  Aron  13  an  average  man  of  50  to  55  kilograms 
weight  in  the  tropical  climate  of  the  Philippines  consumes 
2500  to  2600  calories,  not  less  therefore  than  an  individual 
of  equal  weight  in  temperate  climates),  but  simply  because, 
having  especially  heavy  labor  to  perform,  they  eat  a  corre- 
spondingly large  amount ;  and  the  result  is  that  they  obtain 
the  necessary  amounts  of  protein  from  the  large  quantities 
of  food  ingested  even  if  it  be  poor  in  protein.  For  hard- 
working country-people,  therefore,  a  preponderating  vege- 
tarian diet  is  possible.  For  persons  with  a  predominatingly 
sitting  or  standing  habit  of  life  Cohnheim  would  hold  this 
to  be  a  mistake,  however,  and  he  would  not  regard  the  crav- 
ing of  the  industrial  worker  for  a  full  meat  diet  as  nothing 
more  than  a  "sensual  craving"  (as  many  concerned  with 
public  welfare,  belonging  to  the  ruling  classes,  are  disposed 
to  look  upon  it),  but  an  entirely  proper  demand  based  upon 
physiological  reasons.  This  shows  that  the  deplorable  op- 
position to  the  importation  of  cheap  foreign  meat  is  doubly 
objectionable,  and,  too,  more  fortunately,  as  entirely  without 

12Oshima,  cited  by  L.  Mendel,  Ergebn.  d.  Physiol.,  11,  485,  1911. 
13 H.  Aron    (Manila),  Philippine  Jour,  of  Science,  4,  195,  1909,  cited  in 
Biochem.  Centralbl.,  1909. 


488  NUTRITIONAL  REQUIREMENTS 

fore-sight.  It  makes  little  difference  how  little  influence 
physiologists  may  individually  possess ;  physiology  is  never- 
theless a  powerful  mistress.  When  man  has  found  something 
nature  requires  for  life,  he  has  thus  far  at  least  generally 
known  a  way  to  procure  it. 

Vegetarianism. — This,  then,  brings  us  to  the  considera- 
tion of  the  important  subject  of  vegetarianism. 

There  is  no  question,  of  course,  but  that  human  beings 
are  capable  of  continuously  maintaining  their  bodily  and 
mental  ability  even  on  unmixed  vegetable  diet.  A  Japan- 
ese author  has  shown,  from  collective  inquiry  of  two  hundred 
persons  who  have  all  exceeded  a  century  of  life,  that  about 
one-third  lived  mainly  upon  vegetarian  food  (had  scarcely 
once  a  week  eaten  even  fish) ;  about  half  were,  however,  for 
years  strict  vegetarians,  who  refused  eggs,  milk  and  animal 
fat.  Among  the  Japanese  Buddhists  of  strict  sect  there 
seem  to  be  individuals  who  manage  to  get  on  with  a  remark- 
ably small  amount  of  food  (consisting  of  rice,  radishes  and 
various  greens),  and  who  acquire  a  condition  in  which  they 
can  very  readily  handle  vegetables,  but  for  whom  a  sudden 
change  to  animal  food  is  decidedly  harmful.14  (According 
to  statements  of  various  authors  0.6  gram  of  protein  pro 
kilogram  a  day  may  be  regarded  as  the  low  limit  of  protein 
requirement.)  15 

Generally,  however,  investigations  of  recent  years  are 
not  favorable  to  vegetarianism.  Thus  Caspari 16  from  his 
intensive  studies  regards  a  pure  vegetable  diet,  because  of 
the  difficulty  of  utilizing  it  in  the  body,  its  insipidity  and  its 
large  volume,  as  injudicious  and  its  merits  (low  amount  of 
uric  acid  forming  substances,  etc.)  as  doubtful.     Individual 


"G.  Yukawa  (Osaka),  Arch.  d.  Verdauungskr.,  15,  471,  740,  1909;  cf. 
also  W.  G.  Little  and  Charles  E.  Harris  (Liverpool),  Biochem.  Jour.,  2,  230, 
1907. 

15  C.  von  Noorden,  E.  Voit  and  Constantinidi,  Caspari;  cf.  Hammersten's 
Lehrb.,  p.  858,  1910. 

10  W.  Caspari,  Pflüger's  Arch.,  109,  473,  1905;  cf.  also  the  Literature  in 
Stiihelin   (Basel),  Zeitschr.  f.  Biol.,  Jt9,  199,  1907. 


VEGETARIANISM  489 

attempts  to  give  vegetarianism  a  dynamic  basis  seem  to  be 
misplaced.17  Albertoni  and  Eossi 18  have  conducted  ex- 
haustive metabolic  investigations  upon  Italian  country  peo- 
ple from  the  Abruzzi,  who  (at  a  food-cost  of  about  fifteen 
centimes  a  day  for  each)  live  their  whole  lives  upon  vegetable 
food,  eating  perhaps  a  little  pork  three  or  four  times  a  year. 
The  Italian  investigators  were  able  to  satisfy  themselves 
that  this  mode  of  living  has  an  unfavorable  influence  upon 
development,  and  that  the  addition  of  meat  results  in  an 
improvement  in  the  general  health,  in  the  utilization  of  the 
food,  improvement  in  weight  and  strength,  and  raising  the 
haemoglobin.  It  is,  of  course,  impossible  to  exclude  the 
chance  that  a  corresponding  improvement  of  the  food  of 
strictly  vegetable  type  might  perhaps  exert  a  similarly 
favorable  effect. 

The  observations  made  by  the  American  physiologist, 
Slonaker,19  seem  of  even  greater  importance.  This  investi- 
gator separated  a  number  of  young  rats  of  the  same  age  into 
two  groups  and  reared  them  under  the  same  conditions,  with 
this  difference,  that  those  of  one  group  were  fed  exclusively 
upon  vegetables,  those  of  the  other  upon  the  same  materials 
with  the  addition  of  meat.  As  a  result  it  appeared  that  the 
growth  of  the  vegetarian  animals  was  decidedly  retarded,  the 
animals  were  weakly  and  much  more  apathetic  than  their 
omnivorous  comrades ;  they  became  senile  much  earlier,  and 
their  average  length  of  life  was  only  about  half  that  of  the 
second  group.  Collectively  the  omnivorous  rats  lived  longer 
than  even  those  individuals  of  the  other  group  which  at- 
tained the  greatest  age.  These  results  are  of  such  a  char- 
acter that  the  experience  gained  upon  rats  may  be  directly 
applied,  if  we  wish  to  protect  man  from  such  effects,  to 
human  beings. 

17  M.  Bircher-Benner,  Grundzüge  der  Ernährungstherapie,  3d  ed.,  Berlin, 
0.  Salle,  1909;  cf.  references  of  N.  Zuntz,  Biochem.  Centralbl.,  8,  No.  2178,  1909. 

18  P.  Albertoni  and  Rossi  (Bologne),  Arch.  f.  exper.  Pathol.,  Schmiedeberg 
Festschr.,  29,  1908,  and  6^,  439,  1911. 

19  J.  R.  Slonaker,  Stanford  University  Publications,  1912. 


4<J0  NUTRITIONAL  REQUIREMENTS 

Doubtless  much  depends  upon  the  quality  of  the  vege- 
table food.  It  is  well  known  that  the  occurrence  of  pellagra 
has  by  many  been  attributed  to  an  almost  exclusive  maize 
diet;  it  is  worth  noting  that  zein  (a  protein  substance  which 
represents  the  bulk  of  the  proteid  material  in  the  maize 
grain,  and  which  is  distinguished  by  the  absence  of  the  tryp- 
tophane group,  of  glycocoll  and  lysin)  has  been  proved  to 
be  badly  suited  as  a  continuous  food  for  guinea  pigs  and 
mice.20 

Mechanical  Preparation  of  Vegetable  Food. — Hans 
Friedenthal  has  recently  directed  attention  to  a  new  side  of 
the  vegetarian  problem,  which,  to  the  author,  seems  to  pre- 
sent a  phase  of  great  interest.  In  a  general  way,  we  are 
only  able  to  get  the  good  out  of  those  parts  of  plants  which 
are  stocked  with  reserve  substances  (like  fruit,  roots  and 
tubers) ;  while  those  very  parts  of  plants  which  are  richest 
in  protein,  the  leaves,  cannot  be  utilized  either  in  the  raw 
or  after  cooking.  It  seems,  however,  that  it  is  possible  by  a 
method  of  very  fine  mechanical  comminution  to  pulverize 
dried  green  plants  in  such  a  way  that  the  greater  part  of  the 
cell  walls  are  broken  up  and  the  cell  contents  made  available 
for  the  action  of  the  digestive  juices.  By  this  method  we 
can  obtain  the  green  plants  in  the  form  of  a  fine  powder, 
which,  in  passing  through  the  intestine,  does  not  induce  an 
increased  peristalsis  as  the  ordinarily  ingested  gross  vege- 
table structures  regularly  do,  and  which  is  digested  with  the 
greatest  ease.  Infants  less  than  six  months  of  age,  to  whom 
hitherto  greens  could  not  be  given  in  any  way,  have  been 
allowed  to  drink  spinach-powder  or  carrot-powder  with  the 
milk  from  a  bottle,  without  the  least  manifestation  of  diges- 
tive disturbances.  It  certainly  is  a  matter  of  considerable 
importance  to  be  able,  with  a  spoonful  of  the  powder  dis- 

20  IS.  Baglioni,  Rend.  Accad.  Lincei,  IT,  609,  cited  in  Centralbl.  f.  Physiol., 
22,  782,  1908;  V.  Henriques  (Copenhagen),  Zeitschr.  f.  physiol.  Chem.,  60, 
105,  1909;  E.  Abderhalden  and  C.  Funk,  Zeitschr.  f.  physiol.  Chem.,  60,  418, 
1909. 


TISSUE  PROTEIN  AND  CIRCULATING  PROTEIN    491 

solved  in  the  milk,  to  administer  to  an  infant  iron,  inorganic 
salts,  nucleins  and  lipoids.  Possibly,  however,  the  matter 
has  even  a  greater  significance,  as  there  seems  to  be  here  a 
hint  of  possibility  of  utilizing  wide  stretches  of  land,  hitherto 
serviceable  to  man's  nutrition  only  by  way  of  the  cattle  in- 
dustry, in  a  much  more  direct  and  rational  manner.21  The 
proposal  to  make  human  beings  become  grass-  and  leaf- 
eaters  may,  perhaps,  at  first  thought  seem  very  ridiculous. 
It  should  not  be  forgotten,  however,  that  it  has  not  always 
been  the  poorest  acquisitions  of  mankind  which  at  the  out- 
start  have  been  recognized  by  the  majority  of  their  con- 
temporaries in  their  humorous  aspect  alone  (witness  steam 
machinery,  illuminating  gas,  and  electricity).  Perhaps  here, 
too,  we  are  confronting  one  of  those  possibilities  destined  to 
take  form  more  easily  for  later  generations  than  for  the  one 
now  in  existence. 

Nitrogen  Balance. — Before  we  can  properly  coordinate 
the  phenomena  of  metabolism  in  fasting  it  is  necessary  that 
we  briefly  (for  it  is  impossible  in  the  course  of  these  lectures 
to  deal  with  detail)  take  up  some  of  the  points  in  relation  to 
protein  metabolism. 

First  the  matter  of  nitrogen  balance :  It  is  well  known 
to  all  that  a  meat  eater  who  has  been  accustomed  to  a  fixed 
meat  ration,  reacts  to  an  increased  or  a  diminished  amount 
of  meat  ingested  by  a  heightened  or  lowered  nitrogen  elimi- 
nation, and  that  after  a  time  there  gradually  comes  to  be 
maintained  an  equilibrium  between  the  total  amount  of  in- 
taken  protein-nitrogen  and  of  the  eliminated  urinary- 
nitrogen. 

Tissue  Protein  and  Circulating  Protein. — This  peculi- 
arity of  the  animal  economy,  which  is  in  effect  that  the 
amount  of  protein  disintegration  is  primarily  determined  by 
the  amount  of  protein  introduced,  led  Voit  to  physiologically 
differentiate  between  tissue-protein  and  circulating-protein. 

aH.  Friedenthal  (Nikolas  Lake  in  Berlin),  Pfliiger's  Arch.,  1^4,  152, 
1912;    Umschau,  1912,  649. 


492  NUTRITIONAL  REQUIREMENTS 

For  decades  the  propriety  of  this  differentiation  has  been  a 
matter  of  contention.  Pflüger  in  particular  has  most  vio- 
lently assailed  it.  The  author  frankly  confesses  that  he  has 
never  fully  appreciated  the  importance  of  this  contention. 
Is  there  anything  so  remarkable  in  the  point  that  con- 
stituents of  the  body,  so  distinct  from  an  anatomical  stand- 
point as  blood-proteins  and  tissue-proteins,  should  from 
many  aspects  also  present  distinctive  physiological  features  f 
Is  it  to  be  assumed  as  a  fact  that  every  protein  which  a  few 
hours  after  a  meal  occasions  an  increased  nitrogen  elimina- 
tion had  previously  become  ' '  organized ' '  ?  Investigations  in 
recent  years  have  clearly  shown  that  a  differentiation 
between  endogenous  and  exogenous  tissue-metabolism  is 
thoroughly  justified;  while  the  urea  elimination  seems  pri- 
marily dependent  upon  the  protein  which  is  introduced  we 
realize  that  the  excretion  of  other  urinary  constituents,  as  the 
oxyproteic  acids,  urochrome,  Creatinin  and  uric  acid,  is  de- 
termined essentially  by  the  break-down  of  tissue.2^  It  may 
be  that  the  author  is  not  enough  of  an  expert  to  be  able  to 
thoroughly  comprehend  fine  points  of  distinction;  but  he 
cannot  rid  himself  of  the  feeling  that  in  the  endless  disputa- 
tions over  these  and  many  related  ideas  there  is  a  trace  of  the 
scholasticism  of  the  Middle  Ages. 

Specific-dynamic  Action  of  Protein. — While  the  introduc- 
tion of  fat  and  of  carbohydrates  in  the  food  leads  to  an  in- 
crease in  the  body  stores,  increase  of  the  proteins  of  the  food 
gives  rise  merely  to  an  increased  protein  exchange.  Accord- 
ing to  Buhner's  theoretical  views  the  protein  undergoes  a 
cleavage  into  a  nitrogenous  and  a  non-nitrogenous  fraction. 
To  the  latter,  along  with  the  carbohydrates  and  fats,  falls  the 
role  of  providing  for  the  energy  requirements  of  the 
economy ;  continuous  combustion  of  the  nitrogenous  moiety, 
in  as  far  as  it  cannot  be  made  of  use  for  purposes  of  tem- 
perature regulation,  leads  to  a  loss  of  energy.23     Increase  of 

58  Cf.  O.  Hammersten'a  Lehrb.,  7th  ed.,  851,  et  seq.,  1910. 
23  Cf.  O.  Hammersten,  1.  c.,  p.  859. 


PHYSIOLOGICAL  VALUE  OF  DIFFERENT  PROTEINS  493 

protein  ingestion  is  not  an  unmixed  good  to  the  adult  body ; 
aside  from  the  fact  that  it  forces  upon  the  kidneys  an  in- 
creased functional  demand,  it  also  makes  increased  demands 
upon  the  provisions  for  temperature  regulation.  Later  on, 
in  connection  with  the  subject  of  heat  production  in  the  body, 
this  particular  point  in  protein  metabolism,  for  which  Rub- 
ner  has  introduced  the  term  ' '  specific-dynamic  action, ' '  will 
be  again  taken  up. 

Physiological  Value  of  Different  Proteins.  Heterospe- 
cific  and  Homospeciftc  Proteins. — The  question  may  here  be 
taken  up,  whether  the  different  proteins  are  to  be  considered, 
as  far  as  their  nutritive  value  is  concerned,  as  physiologically 
equivalent.  It  is  obvious  that  the  organism,  in  order  to  con- 
struct the  proteins  peculiar  to  its  tissues,  makes  use  of 
"building  stones,"  particularly  aminoacids,  in  the  same  pro- 
portion in  which  they  exist  in  the  tissues.  That  the  con- 
struction of  the  body  is  largely  independent  of  the  char- 
acter of  the  food  has  been  shown  by  Abderhalden  and 
Samuely : 24  the  serum  proteins  contain  eight  to  nine  per 
cent,  of  glutaminic  acid,  while  a  vegetable  protein,  gliadin,  is 
made  up  of  about  half  (according  to  T.  B.  Osborne,  43  per 
cent. )  of  this  latter.  It  has  been  shown  that  the  constitution 
of  the  serum  proteins  of  the  horse  is  in  no  wise  disturbed  by 
gliadin  feeding. 

There  is  a  question  here  which  forces  itself  upon  every 
one  who  reflects  upon  protein  metabolism — how  it  happens 
that  the  same  amount  of  protein  which  is  broken  down  in  the 
course  of  fasting  is  not  sufficient  to  maintain  the  body  in 
nitrogen  equilibrium  when  ingested.  C.  Voit  long  since  rec- 
ognized that  if  we  seek  to  maintain  this,  a  multiple  of  the 
nitrogen  which  appears  in  the  urine  in  protracted  fasting 
must  be  given  in  the  form  of  protein.  Michaud25  (inLütlrje's 
Clinic)  has  raised  the  question  whether  it  may  not  perhaps  be 

24  E.  Abderhalden  and  F.  Samuely,  Zeitschr.  f.  physiol.  Chem.,  46,  193,  1905. 

25  L.  Michaud  (Liithje's  Clinic,  Frankfurt  a.  M. ),  Zeitschr.  f.  physiol. 
Chem.,  59,  405,  1909. 


494  NUTRITIONAL  REQUIREMENTS 

that  the  economy,  in  the  introduction  of  heterospecific  pro- 
tein containing  the  protein  "building  stones"  in  different 
quantitative  proportions  than  those  characterizing  the  pro- 
tein of  the  body,  must  not  exert  a  selective  activity  between 
these  components,  throwing  out  the  aminoacids  that  are  in 
excess  and  concentrating  others. ' '  The  process  of  transform- 
ing heterologous  into  homologous  protein,  as  Abderhalden 
depicts  it,  might  well  explain  why  an  animal  with  a  supply 
of  barely  the  minimum  of  protein  of  fasting  cannot  be 
brought  into  nitrogen  balance.  If  this  idea  be  followed,  it 
must  be  theoretically  possible  to  restore  the  nitrogen  balance 
by  limiting  as  far  as  possible  this  necessity  for  selection  in 
regeneration,  and  by  putting  at  the  disposal  of  the  economy 
the  'building  stones'  in  the  same  concentration  in  which  they 
exist  in  the  homologous  protein,  none  of  the  aminoacids  or 
peptids  either  in  extra  or  in  deficient  proportions.  In  other 
words,  we  should  give  an  animal  a  protein  mixture  of  its 
own  body,  that  is,  a  mixture  in  which  the  individual  tissue 
proteins  are  represented  in  exactly  the  same  proportions  as 
they  show  in  their  breaking  down  in  fasting. ' '  Attempts  to 
follow  this  idea  have  been  made,  by  feeding  dogs  after  a 
period  of  fasting,  in  some  instances  with  heterologous  pro- 
teins (gliadin,  casein,  nutrose),  in  others  with  a  broth  made 
up  of  dog  muscle,  various  canine  tissues  and  canine  serum. 
The  result  showed  (as,  too,  in  similar  experiments  carried 
out  by  Hösslin  and  Lesser)26  that  in  a  general  way  it  is  im- 
possible to  maintain  an  animal  in  nitrogen  equilibrium  by 
giving  it  no  more  than  the  equivalent  of  protein  lost  in  fast- 
ing ;  that,  however,  invariably  smaller  amounts  of  homologous 
protein  are  required  to  restore  this  balance  than  would  be 
required  of  heterologous  protein.  The  statements  of  French 
authors  27  are  in  harmony  with  this  view,  in  that  the  protein 

26  H.  v.  Hösslin  and  Lesser  (Halle  und  Mannheim),  Zeitschr.  f.  physiol. 
Chem.,  73,  345,  1911;  cf.  also  F.  Frank  and  A.  Schittenhelm,  ibid.,  70,  99,  1910; 
73,  157,  1911. 

"  H.  Busquet,  Jour,  de  Physiol.,  11,  399,  1909;  G.  Billard  (Clermont- 
Ferrand),  C.  R.  Soc.  de  Biol.,  68,  1103,  1910. 


FOOD  COMPOSED  OF  SIMPLE  SUBSTANCES        495 

supply  of  frogs  is  more  easily  maintained  by  feeding  with 
frog-meat  than  with  the  flesh  of  mammals ;  tadpoles  fed  in 
some  instances  with  frog-liver,  in  others  with  calf -liver,  are 
said  to  thrive  better  in  the  former  case. 

The  idea  that  proteins  of  different  origin  are  not  physio- 
logically equivalent  is  by  no  means  new.  Some  reference  to 
this  point  has  been  made  above,  in  connection  with  the  sub- 
ject of  the  processes  of  resorption  in  the  intestine;  and  the 
statement  was  made,  too,  that  it  has  not  been  found  possible 
to  maintain  the  nutrition  of  an  animal  on  gelatin  as  the  sole 
source  of  nitrogen.  Casein,  gliadin  and,  too,  zein  (to  be 
thought  of  in  connection  with  its  relation  to  pellagra)  may 
also  be  regarded  as  examples  of  proteins  which  do  not  con- 
tain certain  characteristic  "building  stones."  There  are  a 
number  of  comparative  studies  upon  the  physiological  value 
of  different  proteins,  among  which  may  be  especially  men- 
tioned those  of  Böhmann,  Thomas,28  E.  Voit  and  Zisterer,29 
and,  too,  those  of  Osborne  and  L.  B.  Mendel.30  The  last 
named  writer  believes  that  at  present  it  is  too  early  to  come 
to  final  conclusions  upon  this  subject;  that  the  factors  of 
variation  are  too  numerous  to  be  mastered  in  a  few  simple 
equilibrium  experiments  of  short  duration. 

Food  Composed  of  Simple  Substances. — In  concluding, 
the  interesting  question  of  feeding  animals  on  a  diet  arti- 
ficially constructed  of  elementary  foodstuffs  may  be  properly 
discussed  here. 

The  basic  principle  of  maintaining  animal  life  by  a  mix- 
ture of  simple  nutrient  substances  was  long  since  brought 
forward  by  studies  by  Zadik,  Abderhalden  and  Kona,  and 
by  Henriques  and  Hansen.  Abderhalden  's  recent  investiga- 
tions, which  have  been  presented  above  (p.  64),  indicating 
the  possibility  of  nourishing  animals  on  a  mixture  of  the 


28  K.  Thomas,  Arch,  f .  Anat.  u.  Physiol.,  1909,  219. 

29  E.  Voit  and  J.  Zisterer.  Zeitschr.  f.  Biol.,  53,  157,  457.  1909. 

80  T.  B.  Osborne  and  L.  B.  Mendel,  Carnegie  Institution  of  Washington, 
Publication,  No.  156,  I  and  IV,  1911;  cf.  Literature:  L.  B.  Mendel,  Ergebn. 
d.  Physiol.,  11,  482,  1911. 


496  NUTRITIONAL  REQUIREMENTS 

products  of  hydrolytic  cleavage  of  simple  food  substances,  as 
a  mixture  of  simple  sugars,  higher  fatty  acids,  aminoacids 
and  salts,  make  any  further  brain-racking  efforts  in  this  line 
superfluous.  This  is,  however,  not  to  say  that  such  arti- 
ficially constructed  food  is  fully  equivalent  to  natural  food ; 
this  is  certainly  not  true.  There  are  still  a  great  many  im- 
perfectly studied  factors  involved  which  are  to  be  taken  into 
consideration.  For  example,  although  it  has  not  been  found 
possible  thus  far  to  indefinitely  maintain  the  lives  of  pigeons 
upon  a  mixture  of  simple  food  substances,  this  is  apparently 
due,  as  shown  by  studies  in  the  Munich  Physiological  Insti- 
tute,31 simply  to  the  physical  character  of  the  nutrient  ma- 
terial, which  occasions  severe  inflammatory  processes  in  the 
crop  of  the  birds.  Contrary  to  divergent  findings,32  F.  Böh- 
mann has  shown  that  mice  can  be  kept  alive  very  well  on  a 
nutrient  mixture  of  protein  material,  fats,  carbohydrates  and 
salts.33  What  complicating  factors  are  likely  to  enter  into 
this  type  of  experiments  is  evident  in  the  already  presented 
experiments  of  Stepp,34  who  found  that  mice  would  invari- 
ably die  in  the  course  of  a  few  weeks  on  a  diet,  otherwise 
entirely  sufficient,  from  which  the  contained  lipoids  had  been 
removed  by  means  of  alcohol  and  ether. 

A  valuable  recent  study  by  T.  B.  Osborne  and  L.  B.  Men- 
del 35  has  been  submitted  in  reference  to  rats,  showing  that 
white  rats  serve  as  very  suitable  subjects  for  such  investi- 
gations. The  normal  length  of  life  of  these  animals  is  about 
three  years;  studies  extending  over  the  period  of  a  year 
therefore  include  a  very  considerable  part  of  their  term  of 

31  L.  Jakob  (O.  Frank's  Lab.,  Munich),  Zeitschr.  f.  Biol.,  Jt8,  19,  1906. 
82  W.  Falta  and  C.  T.  Noegerath    (W.  His's  Clinic,  Basel),  Hofmeister's 
Beitr.,  7,  313,  1905;  P.  Knapp  (Basel),  Zeitschr.  f.  exper.  Pathol.,  5,  147,  1908. 

33  F.  Röhmann  (Breslau),  Allgem.  med.  Centralztg.,  1908,  No.  9,  cited  in 
Jahresber.  f.  Tierchem.,  38,  659. 

34  W.  Stepp  (F.  Hofmeister's  Lab.,  Strassburg,  and  Medical  Clinic,  Giessen), 
Biochem.  Zeitschr.,  22,  452,  1909,  and  Zeitschr.  f.  Biol.,  57,  135,  1911. 

35  T.  B.  Osborne  and  L.  B.  Mendel,  1.  c,  and  Science,  n.  s.,  $k,  722,  1911; 
Jour,  of  Biol.  Chem.,  12,  473,  1912;    Zeitschr.  f.  physiol.  Chem.,  80,  307,  1912. 


FOOD  COMPOSED  OF  SIMPLE  SUBSTANCES        497 

existence.  With  favorable  hygienic  conditions  and  careful 
attention  made  possible  in  the  study  by  the  assistance  of  the 
Carnegie  Institution,  they  succeeded  in  keeping  rats  on  arti- 
ficial diet  for  a  great  part  of  their  lives.  A  diet  of  the  type 
in  mind  was  made  up  of  a  mixture  of  milk  powder,  starch, 
pork  fat  and  salts.  If  milk  was  freed  of  its  proteins,  and  the 
remainder  concentrated,  it  proved  to  be  a  suitable  supple- 
ment for  different  forms  of  protein  diet,  to  such  a  degree 
in  fact  that,  even  when  they  fed  isolated  proteins,  marked 
growth  of  young  animals  was  induced.  By  this  method  the 
possibility  of  making  comparisons  between  different  proteins 
was  afforded.  Casein,  lactalbumin,  crystallized  eggalbumin 
and  edestin,  and  the  glutein  from  wheat  and  glycinin  from 
the  soya  bean  proved  to  be  of  full  value.  Gliadin  (from 
wheat)  and  hordein  (from  barley) ,  in  the  catabolism  of  which 
glycocoll  and  lysin  enter  but  little,  proved  to  at  least  have 
the  power  of  keeping  the  bodies  of  the  rats  in  statu  quo, 
although  without  growth ;  and  zein,  the  tryptophan-,  lysin- 
and  glycocoll-free  protein  of  maize,  as  also  gelatine,  were 
found  insufficient  even  for  this  last  purpose.  It  was  repeat- 
edly noted  that  proteins  devoid  of  the  cyclical  molecules  of 
tyrosin  and  tryptophane  were  apparently  not  suitable  for 
satisfying  the  requirements  of  growth.  With  this  in  mind 
Osborne  suggested  the  hypothesis  that  "cyclopoiesis"  (that 
is,  ability  to  build  up  certain  cyclical  molecules)  is  a  char- 
acteristic of  the  vegetable  cell,  and  that  for  this  reason  the 
animal  body  may  be  supposed  to  be  dependent  for  certain 
types  of  its  nutriment  upon  vegetable  life. 

Investigations  along  similar  lines  have  very  recently  been 
made  in  Cambridge  by  Hopkins :  Rats  were  fed  in  parallel 
experiments  on  mixtures  of  casein,  fat,  carbohydrates  and 
salt,  with  and  without  addition  of  a  minimal  quantity  of  fresh 
milk.  Although  this  last  addendum  formed  scarcely  four 
per  cent,  of  the  total  food  in  its  dried  state,  it  made  possible 
a  normal  and  continued  growth;  while  the  rats  fed  on  the 

32 


498  NUTRITIONAL  REQUIREMENTS 

milk-free  mixture  remained  stationary  in  their  develop- 
ment.36 

Velocity  of  Protein  Catabolism  in  Metabolism. — Another 
problem  of  metabolism  which  has  received  much  attention 
is  that  involving  the  rapidity  of  protein  break-down  in 
metabolism.  A  very  large  number  of  studies  37  may  be  inter- 
preted somewhat  as  follows :  The  velocity  of  decomposition 
of  ingested  proteins  depends  upon  the  state  of  nutrition  and 
is  the  more  marked  the  longer  a  preceding  period  of  hunger 
has  existed.  Postcoenal  urea  elimination  in  normal  human 
beings  shows  a  maximum  reached  in  from  the  fourth  to  the 
fifth  hour ; 38  if,  however,  the  nitrogen-bearing  nutrient  mat- 
ter is  given  in  the  form  of  protein  in  advanced  cleavage  the 
maximum  urea-elimination  appears  earlier  (in  the  course  of 
the  first  hour) .  Elimination  of  nitrogen  and  that  of  sulphur 
often,  but  not  invariably,  proceed  in  parallel  lines ;  in  many 
instances  the  sulphur  fraction  appears  to  be  the  first  to  be 
attacked  in  the  cleavage  of  the  protein  molecule,  and  the 
elimination  of  sulphur,  as  a  sulphate,  precedes  the  formation 
of  urea.39  The  output  of  ammonia  takes  place  with  greater 
velocity  and  at  times  reaches  its  maximum  in  advance  of  the 
nitrogen  and  sulphur.40  When  the  protein  cleavage  occurs 
with  formation  of  sugar  (as  in  phloridzin  diabetes)  glucose 
is  excreted  before  the  nitrogen.41  The  carbon  coming  from 
the  protein  is  eliminated  by  the  lungs  (according  to  Frank 

36 F.  Gowland  Hopkins  (Physiol.  Lab.,  Cambridge),  Jour,  of  Physiol.,  44, 
425,  1912. 

87  C.  Voit,  C.  Ludwig,  Panum,  Falck,  Feder,  Sonden  and  Tigerstedt,  Lander- 
gren,  Reilly,  Nolan  and  Lusk,  Sherman  and  Hawk,  Slosse,  Frank  and  Tromms- 
dorf,  Vogt,  Falta,  Gigon  and  Pari,  Marriott  and  Wolf,  Camerer,  Asher  and 
Haas,  Levene,  Stauber,  Wolf  and  Österberg,  and  others.  Cf.  Literature: 
R.  Tigerstedt,  Nagel's  Handb.  d.  Physiol.,  1,  392,  412-1905;  A  Stauber  (E. 
Freund's  Lab.,  Vienna),  Biochem.  Zeitschr.,  25,  187,  1910;  C.  G.  L.  Wolf 
(Cornell  Univ.,  New  York),  ibid.,  40,  194,  1912;   41,  111,  1912. 

38  According  to  Asher  and  Haas  and  to  A.  Stauber. 

39  Cf.  J.  Hämäläinen  and  W.  Helme  (Helsingfors),  Skandin.  Arch.  f. 
Physiol.,  19,  182,  1907. 

40  C.  G.  L.  Wolff,  1.  c. 

41  Lusk  and  bis  collaborators. 


ENDURANCE  OF  HUNGER  AND  THIRST  499 

and  Trommsriorf)  more  quickly  than  by  the  kidneys.  An 
important  point  determined  in  these  studies  is  the  fact  that 
excretion  of  Creatinin,  uric  acid,  and  oxyproteic  acids  is  not 
influenced  in  any  material  degree  by  protein  ingestion. 

Ernest  Heilner 's  observation  is  of  considerable  interest 
in  this  connection,  showing  that  urea  introduced  subcutane- 
ously  has  a  stimulative  effect  on  protein  metabolism,  thus 
suggesting  the  possibility  of  urea  itself  being  a  factor  in  the 
special  mechanism  regulative  of  the  course  of  intracorporeal 
protein  disintegration.42 

METABOLISM  IN  FASTING 

We  may  now  proceed  to  outline  the  information  we  pos- 
sess relative  to  metabolism  in  fasting.43  It  is  the  author's 
purpose  to  set  forth  only  the  most  interesting  points  which 
have  appeared  in  the  extensive  literature  concerning  this 
subject.  It  has  been  so  often  stated  that  these  discussions 
make  no  pretense  to  completeness,  that  it  is  decidedly  super- 
fluous to  repeat  it. 

Hoiv  Long  May  Hunger  and  Thirst  Be  Endured? — 
What  is  the  longest  possible  period  of  endurance  of  absolute 
withdrawal  of  food?  The  professional  faster,  Succi,  fasted 
for  thirty  days ;  the  American  physician,  Dr.  Tanner,  for 
forty  days ;  and  Merlatti  in  Paris  for  as  much  as  fifty  days— 
although  it  must  be  noted  that  the  last  drank  water  and  that 
Succi  took  large  doses  of  opium  to  allay  his  gastralgia.  Adult 
dogs  can  be  kept  alive  certainly  as  much  as  sixty  days  in  a 
state  of  absolute  carency.  The  author  would  not  grant  any 
very  great  importance  to  the  isolated  observation  of  Kuma- 
gawa,  whose  experiment  animal  died  on  the  ninety-eighth  day 

42  E.  Heilner  (Physiol.  Instit.,  Munich),  Zeitschr.  f.  Biol.,  52,  216,  1909. 

43  Literature  upon  Metabolism  in  Fasting:  S.  Weber,  Ergeb.  d.  Physiol.,  V , 
701-746,  1902;  R.  Tigerstedt,  Nagel's  Handb.  d.  Physiol.,  1,  375-391,  1905; 
A.  Magnus-Levy,  Handb.  d.  Pathol,  d.  Stoffw.,  2d  ed.,  1,  310-315,  1906;  C.  von 
Noorden,  ibid..  1,  480-547,  1906;  Benedict,  Metabolism  in  Inanition,  Carnegie 
Institution,  Washington,  1907;  T.  Brugsch,  Handb.  d.  Biochem.,  y,  284-306, 
1908;  R.  Tigerstedt,  ibid.,  4",  55-66,  1910;  Graham  Lusk,  Ernährung  u.  Stoffw., 
38-70,  1910. 


500  METABOLISM  IN  FASTING 

of  fasting,  with  a  loss  in  weight  from  the  original  seventeen 
kilograms  down  to  six  kilograms;  as  experimental  faults, 
such  as  an  occasional  clandestine  feeding  by  some  compas- 
sionate hand,  can  scarcely  be  entirely  excluded  in  practice. 
American  authors  have  recently  obtained  information  for 
publication  of  a  dog  which  withstood  one  hundred  and  seven- 
teen days  of  hunger  and  a  loss  of  sixty-three  per  cent,  in 
weight.44 

When  water  is  withdrawn  at  the  same  time  hunger  can- 
not be  withstood  for  nearly  the  same  length  of  time.  In  this 
case  the  water  required  for  solution  of  the  urea  is  abstracted 
from  the  tissues.  Straub  observed  in  his  thirsting  dogs,  fed 
on  dried  meat  and  fat,  a  loss  of  one-fifth  of  the  water  con- 
tained in  the  muscles ;  yet  in  these  cases  the  mode  of  feeding 
could  not  be  continued  very  long  because  of  intestinal  dis- 
turbances and  vomiting  of  the  ingested  food.  According  to 
Bubner  pigeons  die  after  four  or  five  days  if  allowed  to 
hunger  and  thirst,  but  can  be  kept  alive  for  twelve  days  if 
given  water.  As  a  rule,  fasting  human  beings  do  not  drink 
a  great  deal  of  water,  as  water  is  produced  in  the  course  of 
combustion  of  the  tissues  and  the  amount  of  digestive  juices 
secreted  is  very  small. 

Loss  of  Weight  of  the  Organs. — Death  of  animals  in  in- 
anition occurs  after  at  least  from  one-third  to  one-half  of 
their  weight  has  been  lost.  If  one  considers,  however,  the 
total  amount  of  consumable  material  only,  the  loss  at  time  of 
death  may  amount  to  as  much  as  seventy  per  cent.  The  loss 
of  weight  in  starved  animals  is  distributed  (as  indicated  by 
the  studies  of  Chossat,  Voit,  Kumagawa,  Sedlmair  and 
others)  unevenly;  the  adipose  tissue  being  seriously  in- 
volved, a  loss  of  ninety  per  cent,  or  more  of  this  being  pos- 
sible. The  muscles,  the  large  glands  and  the  blood  may  lose 
as  much  as  half  their  substance ;  while  the  central  nervous 
system  remains  almost  unchanged  in  weight.    The  skeletal 

"P.  E.  Howe,  H.  A.  Matill  and  P.  B.  Hawk  (Univ.  of  Illinois),  Jour,  of 
Biol.  Chem.,  11,  103,  1912. 


TOTAL  METABOLISM  IN  INANITION  501 

muscles  are  affected  in  a  higher  degree  than  the  heart ;  Voit 
calculated  in  case  of  the  cat  that  while  the  muscles  had  lost 
thirty  per  cent,  in  weight,  the  heart  had  been  reduced  only 
three  per  cent.  However,  the  statements  recorded  in  refer- 
ence to  this  point  in  literature  are  contradictory. 

As  far  as  the  blood  is  concerned,  the  most  constant  change 
seems  to  be  a  relative  increase  of  its  globulins  as  contrasted 
with  the  albumins  (as  observed  by  Burckhardt,  Githens, 
Wallerstein  and  others).  This  is  accounted  for  in  different 
ways,  in  the  first  place  as  due  to  a  passing  of  the  globulins 
out  of  the  tissues,  and  in  the  second  place  on  the  ground  that 
albumin  principally  is  derived  from  the  food ;  however,  the 
connection  is  not  clear.  Sometimes,  too,  it  is  said  that  there 
is  a  "thickening,"  or,  on  the  other  hand,  that  there  is  an 
' '  atrophy ' '  of  the  blood  (where  it  is  held  there  is  a  loss  of  its 
formed  elements  proportionate  to  the  body  mass).  The  in- 
creased amount  of  fat  in  the  blood  in  inanition  is  striking 
(vide  infra).  Some  have  regarded  observations  of  Landois 
upon  artificial  plethora  by  injection  of  blood,  in  which  condi- 
tion the  excess  of  serum  proteins  as  circulating  protein  is 
easily  used,  but  the  "tissue  protein"  of  the  red  blood  cells 
is  much  more  slowly  broken  down,  as  of  importance  to  our 
conception  of  the  condition  of  the  blood  in  inanition ;  how- 
ever, there  has  not  been  any  important  conclusion  from  it. 
Benedict  has  noted  in  fasting  human  beings  a  progressive 
loss  of  leucocytes,  erythrocytes  and  haemoglobin. 

Total  Metabolism  in  Inanition. — What  then  of  the  gen- 
eral exchange  in  fasting? 45  It  might  be  expected  in  the  first 
place  that  the  fasting  individual  would  lower  his  require- 
ment. This,  however,  is  not  the  case ;  in  spite  of  expendi- 
ture of  the  body  substance  proper,  the  organism  is  unable  to 
materially  lower  its  exchange  below  that  of  normal  nutrition. 
It  is  true  the  energy  consumption  is  lowered  from  day  to  day, 
but  at  the  same  time  the  body  weight  also  is  diminished.    If 

46  Cf .  Literature  upon  Energy  Exchange  in  Inanition :  R.  Tigerstedt, 
Handb.  d.  Biochem.,  4"  55-66,  1910. 


502  METABOLISM  IN  FASTING 

the  energy  consumption  be  determined  in  proportion  to  the 
kilogram  of  body  weight  a  striking  uniformity  becomes  evi- 
dent, about  28  to  32  calories  pro  kilogram  for  the  twenty- 
four  hours.  In  case  of  rest  in  bed  the  minimal  requirement 
of  a  human  being  was  determined  as  somewhat  less  by  Tiger- 
stedt  and  by  Johansson,  twenty-two  to  twenty-five  calories 
daily  pro  kilogram.  Atwater  and  Benedict  found  in  fasting 
human  beings  resting  in  bed  an  energy  consumption  of 
twenty  to  twenty-one  calories  by  direct  calorimetry ;  Zuntz, 
in  case  of  an  individual  accustomed  to  a  diet  very  low  in 
protein  (consisting  of  potatoes  and  butter),  at  absolute  rest 
and  fasting,  met  with  a  twenty-four  hour  energy  consump- 
tion of  only  about  nineteen  calories  pro  kilogram.46  Ob- 
servations of  the  respiratory  metabolism  and  nitrogen  out- 
put have  shown,  further,  that  not  only  the  total  expenditure 
of  energy  but  also  the  amount  of  protein  and  fat,  which 
provides  the  latter,  are  fairly  constant  in  the  body.  It  should 
be  noted,  too,  that  the  economy  begins  its  actual  fasting  state 
only  after  the  lapse  of  several  days,  after  the  greater  glyco- 
gen deposits  have  been  consumed.  The  constancy  of  the 
exchange  in  inanition  is,  however,  not  confined  merely  to 
human  beings.  E.  Voit  found  in  case  of  all  warm  blooded 
animals  studied  a  relative  uniformity  of  energy  requirement 
in  inanition  if  it  be  determined  for  the  unit  of  surface.47  ' '  I 
conclude  directly,"  says  Eubner,  "that  the  developing  ani- 
mal in  its  growth  manifests  a  very  varying  intensity  of  gen- 
eral metabolism  in  inanition,  but  that  invariably  the  intensity 

48  N.  Zuntz,  Centralbl.  f.  Physiol.,  26,  725,  1912. 

"  Note :  "  The  minimal  maintenance  work  of  the  fattened  and  the  non- 
fattened  growing  animal,"  says  Tangl,  in  a  study  of  the  minimal  maintenance 
effort  of  the  hog  (Biochem.  Zeitschr.,  44,  278,  1912),  "show  scarcely  any 
difference,  when  calculated  on  the  basis  of  the  surface  extent  of  the  body;  cal- 
culated on  the  basis  of  body  weight  it  is  greater  for  the  growing  unfattened 
animal.  As  an  average  it  is  for  the  fattened,  pro  kilogram  19.6  calories,  pro 
square  metre  1060  calories;  for  the  unfattened,  pro  kilogram  27.2  calories, 
pro  square  metre  1100  calories.  It  is  in  each  instance  noteworthy  that  in  spite 
of  the  difference  in  the  amount  of  fat  in  the  fattened  and  unfattened  animals 
the  maintenance  work  determined  on  the  basis  of  a  unit  of  body  surface  is 
the  same     .     .     ." 


PROTEIN  ECONOMICS  IN  INANITION  503 

is,  under  similar  conditions,  only  an  expression  of  the  relative 
surface  development. ' ' 4S  Eef erence  will  hereafter  be  made 
to  the  objections  to  this  view.  That  active  effort  in  the  state 
of  inanition  must  necessarily  raise  the  energy  requirement, 
is  obvious ;  Pettenkof  er  and  Voit  in  such  case  were  always 
able  to  show  a  greatly  increased  fat  break-down. 

Protein  Economics  in  Inanition. — The  curve  of  nitrogen 
elimination  presents  a  fairly  characteristic  course  for  the 
protein  management  in  fasting.49  During  the  first  days  of 
fasting  it  seems  to  be  influenced  by  the  previously  ingested 
food50  until  the  supplies  of  "labile  protein"  and  glycogen 
in  the  system  have  been  consumed.  The  consumption  of  the 
latter  substance  especially,  according  to  Prausnitz  and 
Landergren,  is  usually  followed  by  an  increase  in  the  pro- 
tein exchange  after  the  course  of  the  first  few  days.  Then, 
however,  the  protein  exchange  gradually  falls  in  the  further 
continuation  of  starvation.  By  far  the  greatest  proportion 
of  energy  used  in  inanition,  about  ninety  per  cent,  as  an 
average  in  man,  is  accomplished  at  the  expense  of  the  dimin- 
ishing fat  supply.  Only  at  the  close,  after  the  stored  fat 
has  been  reduced  to  small  residua,  does  an  antemortem  nitro- 
gen-increase make  its  appearance.  This  is  usually  regarded 
as  due  to  the  impoverishment  in  fat  making  itself  felt.  There 
is  no  question  but  that  a  fat  animal  will  withstand  starva- 
tion longer  than  one  poor  in  fat.  F.  N.  Schulz  believes  that 
the  antemortem  rise  in  nitrogen  elimination  is  determined 
not  so  much  by  a  lack  of  fat  as  by  a  sudden  necrosis  of  nu- 
merous badly  involved  cells ;  but  this  suggestion  is  contra- 
dicted by  the  Voit  school.  Tigerstedt  thinks  that  perhaps  it 
may  be  due  to  some  kind  of  intoxication.  The  fact  that 
residual  fatty  tissue  is  to  be  found  in  starved  animals  cannot, 
in  the  writer's  opinion,  be  accepted  as  proof  against  the  view 

4S  Cf.  Th.  Brugsch,  1.  c,  p.  288. 

^Literature  upon  Protein  Conservation  in  Inanition:  A.  Magnus-Levy, 
Handb.  d.  Pathol,  d.  Stoffw.,  2d  ed.,  310-315,  1908. 

00 Cf.  G.  Kinberg  (Stockholm),  Skandin.  Arch.  f.  Physiol.,  25,  291,  1911. 


504  METABOLISM  IN  FASTING 

that  the  antemortem  nitrogen  rise  is  brought  on  by  the  lack 
of  fat ;  it  might  easily  be  conceived  that  the  last  portions  of 
the  fat  are  liquidated  with  much  more  difficulty  than  the 
principal  mass  of  the  fat  deposits.  According  to  Reicher  51 
the  particles  of  fat  in  the  blood,  visible  as  ultramicroscopic 
particles  (steatoconiae)  disappear  in  a  suggestive  manner  at 
the  time  of  the  antemortem  nitrogen  rise.  From  the  studies 
of  Abderhalden  and  his  associates  52  no  evidence  exists  for 
the  supposition  that  there  is  a  change  in  the  chemical  char- 
acter of  the  body  proteins  from  inanition. 

In  view  of  the  fact  that  access  to  water  prolongs  the  life 
of  fasting  animals,  it  is  strange  that,  as  found  by  Heilner,  in 
a  fasting  animal  (contrasted  with  a  well  fed  animal)  it  occa- 
sions an  increase  of  nitrogen  elimination,  referable  to  in- 
crease of  break-down  of  nitrogenous  body  substance,  but  not 
to  a  flushing  out  of  end-products  of  metabolism.53 

Carbohydrate  Metabolism. — The  nitrogen  exchange  of  a 
fasting  animal  is  by  no  means  the  same  thing  as  the  minimal 
nitrogen  metabolism.  By  feeding  carbohydrates  there  is 
accomplished  a  sparing  of  protein  depending  on  the  amount 
of  food,  possibly  (according  to  investigations  made  in  the 
laboratory  of  E.  Voit)  reaching  in  maximum  nearly  fifty-five 
per  cent.54  The  nitrogen  elimination  in  the  urine,  which  in  a 
fasting  human  being  is  seldom  less  than  ten  grams,  may,  ac- 
cording to  Landergren,  be  reduced  by  free  exhibition  of 
carbohydrates  and  fat  to  five  or  six  grams,  or  even  less. 

The  supposition  that  glycogen  disappears  rapidly  and 
completely  from  the  body  of  a  fasting  individual  has  under- 
gone, as  previously  stated,  some  modification,  as  a  result  of 
recent  investigations  upon  the  subject  of  formation  of  sugar 
from  protein.    It  is  now  realized  that  in  an  individual  ren- 

61 K.  Reicher  (Berlin),  Zeitschr.  f.  exper.  Pathol.,  5,  750,  1909. 

52  E.  Abderhalden,  P.  Bergell  and  T.  Dörpinghaus,  Zeitschr.  f.  physiol. 
Chem.,  41,  153,  ly04. 

53  E.  Heilner  (C.  Voit's  Lab.),  Zeitschr.  f.  Biol.,  47,  539. 

MM.  Wimmer  (Physiol.  Instit.,  Veterinary  High  School,  Munich),  Zeitschr. 
f.  Biol.,  57,  185,  1911. 


THE  URINE  IN  INANITION  505 

dered  almost  free  of  glycogen  by  fasting  there  may  take  place 
formation  of  glycogen  de  novo.  Thus  Zuntz  observed,  in 
rabbits  which  had  lost  almost  all  their  glycogen  from  com- 
bined inanition  and  strychnine  convulsions,  the  reappearance 
of  glycogen  at  the  conclusion  of  a  protracted  chloral  nar- 
cosis.55 After  all  that  has  been  said  of  the  formation  of 
sugar  in  connection  with  phloridzin  diabetes  and  pancreatic 
diabetes,  there  is  little  occasion  for  surprise  in  this.  Stiles 
and  Graham  Lusk  observed  in  a  fasting  dog  poisoned  with 
phloridzin  that  while  the  amount  of  nitrogen  eliminated  un- 
derwent diminution  the  sugar  formation  fell  at  the  same 

D  56 

time,  thus  maintaining  unaltered  the  quotient  N~ 

The  Urine  in  Inanition. — The  acidosis  of  inanition  is  a 
striking  anomaly  of  metabolism.  Reference  to  this  phe- 
nomenon has  been  made  above  in  connection  with  the  acetone 
bodies,  where  it  was  stated  that  we  have  every  reason  to  look 
upon  the  formation  of  /?-oxybutyric  acid  and  diacetic  acid  in 
the  fasting  individual  as  related  to  the  breakdown  of  fat. 
The  proportion  of  acetone  bodies  in  inanition  urine  may  at 
times  be  very  considerable;  thus  D.  Gerhardt  and  W. 
Schlesinger  found  in  a  case  of  hysterical  vomiting  forty 
grams  of  oxybutyric  acid  in  the  urine  in  the  course  of  twenty- 
four  hours.  The  natural  result  of  the  abnormal  acid  produc- 
tion in  the  body  is  an  increased  elimination  of  ammonia  in  the 
urine;  Brugsch  observed  as  much  as  thirty-five  per  cent, 
of  ammonia  nitrogen.  For  fuller  details  in  this  connection 
reference  may  be  made  to  the  monograph  of  C.  von 
Noorden.57 

A  great  deal  of  trouble  has  been  expended  upon  the  analy- 
sis of  inanition  urine.  From  among  the  discoveries  which 
have  invariably  rather  poorly  rewarded  the  labor  expended 
in  this  direction,  special  mention  may  be  made  of  the  observa- 

06  Cf .  Literature  ( N.  Zuntz  and  Vogelius,  Nebelthau,  Kiilz,  Frenzel )  ;  Th. 
Brugsch,  1.  c,  p.  300. 

56  Stiles  and  Graham  Lusk,  Amer.  Jour,  of  Physiol.,  10,  77,  1903. 

57  C.  von  Noorden,  1.  c,  pp.  529-536. 


506  METABOLISM  IN  FASTING 

tions  of  Benedict  and  Cathcart  in  reference  to  the  increase  of 
creatin  in  comparison  with  Creatinin  and  the  occasionally 
noted  occurrence  of  "albumoses."58 

Respiratory  Quotient. — Much  attention  has  been  given  to 
observations  upon  the  matter  of  the  respiratory  quotient  in 
inanition.  As  the  fasting  individual,  after  the  glycogen  sup- 
plies have  been  used  up,  lives  upon  fat  and  protein  the  respir- 
atory quotient  must  lie  between  the  figures  of  protein  break- 
down (0.8)  and  of  fat  decomposition  (0.7).  Benedict,  as  a 
matter  of  fact,  from  experiments  upon  fourteen  fasting 
human  beings  in  Atwater's  respiration  apparatus,  found  in 
all  after  the  first  day  of  fasting  that  the  quotients  were  very 
uniformly  0.74.59 

Hibernation. — Inanition  experiments  of  the  greatest  in- 
terest may  be  observed  in  nature  in  case  of  hibernating  ani- 
mals. In  these  the  exchange  is  found  very  much  lowered 
when  the  temperature  falls  to  16°  to  12°  C. ;  as  in  the  case  of 
the  hedgehog,  to  one-tenth  to  one-twentieth  of  the  normal ;  in 
the  dormouse,  it  is  said,  even  to  one-hundredth.  Studies 
have  been  made  upon  marmots  and  bats  also.  Observation  of 
the  respiratory  quotient  in  such  animals  shows  completely 
paradoxical  results ;  at  times  the  figure  is  remarkably  low, 
less  than  has  ever  been  observed  in  any  other  conditions 
(below  0.5,  even  down  as  low  as  0.23 ).60  Only  a  small  frac- 
tion of  the  oxygen  taken  in  appears  as  carbon  dioxide  in 
these  animals,  a  point  which  must  be  interpreted  as  indicat- 
ing that  the  fat  (which  constitutes  the  bulk  of  the  reserve 
material  of  the  hibernating  animal)  is  incompletely  burned. 
However,  there  are  probably  formed  intermediate  oxygen- 

58  Literature  upon  the  Urine  of  Inanition:  Th.  Brugsch,  1.  c,  pp.  301-306. 

08  G.  F.  Benedict,  The  Influence  of  Inanition  on  Metabolism,  published  by 
the  Carnegie  Institution  of  Washington,  1907. 

80  In  hibernating  bats,  however,  according  to  studies  of  P.  Häri  (F.  Tangl's 
Lab.,  Budapesth),  Pfliiger's  Arch.,  130,  112,  1909,  the  respiratory  quotient  is 
generally  not  lower  than  that  found  in  prolonged  inanition  experiments  in 
other  animals  (0.65-0.7)  ;    only  exceptionally  were  the  figures  below  0.5. 


SENSATION  OF  HUNGER  507 

bearing  products  which  are  principally  retained  within  the 
body.  Possibly  we  have  here  instances  of  the  much  debated 
formation  of  carbohydrate  from  fat.  This  retention  of 
oxygen  explains  the  very  odd  feature  of  occasional  accession 
of  weight  by  the  fasting  hibernating  animals.  When  the 
animal  wakes  up  the  respiratory  quotient  rapidly  rises  to 
about  1.0,  corresponding  to  the  combustion  of  carbohy- 
drates.61 

Rhine  salmon;  Batrachian  Larvce. — Other  extremely  in- 
structive experiments  in  the  field  of  the  physiology  of  inani- 
tion provided  by  nature  are  met  in  the  Rhine  salmon  and  ba- 
trachian larvae.  It  is  known  that  the  male  salmon,  when 
ascending  the  Rhine  from  the  sea,  fasts  for  many  months  and 
develops  the  sexual  organs  at  the  expense  of  the  wasting 
musculature.  It  is  also  known  that,  for  example,  the  larva 
of  the  obstetrical  toad  absorbs  its  tail  in  the  course  of  weeks 
of  fasting,  while  the  legs  are  growing  out  from  the  rump.  It 
is,  however,  impossible  to  go  into  further  detail  in  connection 
with  these  remarkable  subjects. 

Sensation  of  Hunger. — A  few  words  more  in  conclusion  in 
reference  to  the  sensation  of  hunger.  This  is  apparently 
conducted  along  the  vagus  paths.  Cocainization  of  the  vagi 
in  the  neck,  and  so,  too,  of  the  pharyngo-oesophageal  mucous 
membrane,  is  said  to  seemingly  remove  in  dogs  the  sensa- 
tions of  hunger  and  thirst.62  According  to  Cannon,  who  has 
graphically  registered  the  gastric  movements  in  man  by 
means  of  a  balloon  inserted  into  the  stomach,  the  feeling  of 
hunger  is  excited  by  contractions  of  the  gastro-intestinal 
canal.63     So  much  for  the  subject  of  inanition. 

61  Literature  upon  Exchange  in  Hibernation :  O.  Polimanti,  Bull,  accad. 
med.  Roma,  SO,  227,  1904;  A.  Löwy,  Handb.  d.  Biochem.,  4',  177-178,  1908; 
F.  Reach  (Durig's  Lab.,  Vienna),  Biochem.  Zeitschr.,  26,  391,  1910;  E.  Wein- 
land  and  M.  Riehl  (Physiol.  Instit.,  Munich),  Zeistchr.  f.  Biol.,  Jt9,  37,  1907. 

62  A.  Valenti  (Pavia),  Arch,  di  farm.,  S,  H.  6,  cited  in  Centralbl.  f.  d. 
ges.  Biol.,  10,  No.  326,  1910. 

63  W.  B.  Cannon  and  A.  L.  Washburn  (Harvard  Medical  School),  Amer. 
Jour,  of  Physiol.,  29,  441,  1912. 


508  PARENTERAL  NUTRITION 

PARENTERAL  NUTRITION 

The  remainder  of  this  lecture  will  be  given  over  to 
the  practically  important  problem  of  parenteral  feeding. 

The  physician  is  often  enough  brought  face  to  face  with 
a  case  in  which  the  incapacity  of  the  diseased  gastro-intes- 
tinal  apparatus  brings  with  it  an  impossibility  of  providing 
the  body  with  the  food  necessary  for  maintenance  of  life. 
Here  the  question  forces  itself  upon  him  whether  it  may  not 
be  possible  to  introduce  the  food  into  the  body,  disregarding 
the  intestinal  tract,  by  direct  "parenteral"  route.  The  feel- 
ing that  this  is  a  problem  in  which  the  physiological  chemist 
can  render  an  important  and  immediate  service  to  the  prac- 
titioner of  medicine  finds  expression  in  the  large  number  of 
experimental  studies,  which  in  the  course  of  the  last  few 
years  have  been  directed  especially  to  the  question  of  paren- 
teral protein  administration.  What  results  have  been 
obtained? 

Parenteral  Introduction  of  Protein. — The  older  physiolo- 
gists were  for  the  most  part  of  the  opinion  that  heterologous 
protein  introduced  into  the  system  is  not  assimilated,  but  is 
simply  passed  out  with  the  urinary  excretion.  This,  how- 
ever, as  a  matter  of  fact  is  by  no  means  entirely  true.  It  is 
true  that  sometimes  an  albuminuria  is  observed  after  par- 
enteral administration  of  protein  64 ;  eggalbumin  seems  to 
pass  into  the  urine  especially  easily.  (In  normal  human  be- 
ings albuminuria  has  been  noted  after  the  ingestion  of  six 
raw  eggs,  evidently  due  to  portions  of  the  albumin  which 
passed  the  intestinal  wall  without  undergoing  cleavage.)65 
However,  elimination  of  this  sort  is  by  no  means  the  rule. 
There  is  no  doubt  that  the  economy  is  able  to  retain  and  con- 
sume large  amounts  of  parenterally  introduced  specifically 
foreign  protein  (among  others,  for  example,  foreign  blood 
serum,66  egg  albumin,67  casein,  68  or  vegetable  albumin69). 

MCf.  W.  Cramer   (Physiol.  Instil,  Edinburgh),  Jour,  of  Physiol.,  37,  146, 
190S;    J.  Castaigne  and  M.  Chiray,  C.  R.  Soc.  de  Biol.,  60,  218,  1906. 
65  W.  Cramer,  1.  c,  p.  157. 


PARENTERAL  INTRODUCTION  OF  PROTEIN       509 

Modern  methods  of  immunity  investigation  (particularly  by 
precipitins  and  anaphylaxes)  make  it  possible  to  follow  up 
the  fate  of  proteins  which  are  introduced  into  the  system ; 
such  substance  may  be  recognized  for  days  in  the  circulating 
blood,  in  the  peritoneal  fluid  and  in  various  tissues.  It  has 
been  found  possible  to  substitute  two-thirds  of  the  required 
food  protein  in  a  dog  by  horse-serum  injected  subcutaneously 
without  disturbing  the  nitrogen  equilibrium.70  Homologous 
protein  is  evidently  better  tolerated  than  foreign  protein.71 
After  free  transfusion  of  homologous  blood  directly  from  an 
artery  of  one  dog  into  a  vein  of  a  second  dog  there  is  usually 
observable  in  the  latter  an  increase  of  the  nitrogen  elimina- 
tion as  evidence  of  an  increased  protein  break-down ; 72 
but  at  times  this  may  not  occur.  Maintenance  of  nitrogen 
equilibrium  seems  impossible,  however,  even  with  infusion  of 
specifically  identical  serum.73  Kornel  v.  Körösy,74  as  well 
as  Levene,  has  been  able  to  prove  (contrary  to  opposed  state- 
ments)75 that  it  is  of  no  consequence,  as  far  as  the  fate  of 
proteins  injected  intravenously  is  concerned,  whether  they 
have  passed  with  the  circulating  blood  through  the  intestinal 
wall  or  not. 

66 E.  Heilner  (Physiol.  Instit.,  Munich),  Zeitschr.  f.  Biol.,  50,  26,  1908; 
P.  Rona  and  L.  Michaelis,  Pfiuger's  Arch.,  12$,  578,  1908. 

87  Cramer,  1.  c;  V.  C.  Vaughn,  J.  G.  dimming  and  C.  B.  M.  Glumphy 
(Univ.  of  Michigan),  Zeitschr.  f.  Immunitätsfor.,  9,  16,  1910. 

68  L.  Michaelis  and  P.  Rona,  Pflüger's  Arch.,  121,  163,  190S. 

69  L.  B.  Mendel  and  E.  W.  Rockwood  (Yale  Univ.),  Amer.  Jour,  of  Physiol., 
12,  336,  1905. 

70  P.  Rona  and  L.  Michaelis,  Pfiüger's  Arch.,  12k,  579,  190S. 

11  U.  Friedemann  and  S.  Isaak,  Zeitschr.  f.  exper.  Pathol.,  .},  830,  1907,  and 
earlier  works;  F.  Lommel  (D.  Gerhard's  Clinic,  Jena),  Arch.  f.  exper.  Pathol., 
58,  50,  1907. 

72  P.  Häri  (F.  Tangl's  Lab.,  Budapesth),  Biochem.  Zeitschr.,  34,  111,  1911; 
cf.  also  H.  D.  Haskins  (Western  Reserve  Univ.),  Jour,  of  Biol.  Chem.,  3,  321, 
1907. 

"G.  Quagaliariello  (Bottazzi's  Lab.,  Naples),  Arch,  di  Physiol.,  10,  150, 
1912. 

"K.  v.  Körösy  (Physiol.  Instit.,  Budapesth),  Zeitschr.  f.  physiol.  Chem., 
69,  313,  1910. 

75 E.  Freund  and  H.  Popper  (Vienna),  Biochem.  Zeitschr.,  15,  272,  1909. 


510  PARENTERAL  NUTRITION 

As  to  the  question  of  the  practical  applicability  of  paren- 
teral introduction  of  protein,  it  should  be  understood  that  the 
procedure  is  anything  but  a  harmless  expedient.76  It  would 
not  necessarily  mean  very  much  that  after  parenteral  intro- 
duction of  protein  an  unusual  amount  of  ammonia  was  noted 
in  the  urine  and  a  percentage  increase  in  the  purin  figures.77 
The  observation  of  an  cedematous  swelling  of  the  mammary 
glands  after  casein  injection  might  be  related  with  a  specific 
sensitivity  of  the  latter  toward  casein.78  But  we  cannot  but 
be  startled  by  statements  like  those  of  Friedemann  and 
Isaak,79  to  the  effect  that  intravenous  introduction  of  serum 
albumen  is  not  followed  by  toxic  effects  in  fasting  dogs,  but 
in  well  fed  animals  in  nitrogen  equilibrium  usually  induces 
symptoms  which  end  in  death.  The  many  experiences  with 
anaphylaxis,  and  the  danger  of  repetition  of  parenteral  in- 
troduction of  protein  brought  to  light  in  recent  years  (the 
"serum  diseases"  from  the  therapeutic  use  of  diphtheria 
antitoxin  serum,  etc.,  undoubtedly  belong  here  in  part)  must 
necessarily  very  much  depress  any  hope  of  making  paren- 
teral protein  feeding  ever  of  any  great  practical  value  in 
medicine.  E.  Heilner80  regards  it  as  probable  that  the 
phenomena  of  "anaphylaxis"  are  due,  not  so  much  to  the 
production  of  abnormal  toxic  intermediate  products  of  pro- 
tein metabolism,  as  to  the  relative  resistance  of  substances 
which  under  other  circumstances  are  rapidly  elaborated. 

Possibly,  however,  a  greater  practical  importance  may 
attach  to  the  parenteral  introduction  of  the  products  of 
hydrolytic  cleavage  of  protein  than  to  the  parenteral  ad- 


76  Cf.  the  careful  investigations  in  Tangl's  Laboratory  by  P.  Häri,  C.  Rud6 
and  S.  Cserna,  and  L.  Ornstein  (Biochem.  Zeitschr.,  kk,  L  40,  94,  140,  1912) 
upon  the  influence  of  intravenous  and  intraperitoneal  infusion  of  blood,  and 
of  subcutaneous  feeding  with  bloodserum-glucose  mixtures. 

n  S.  v.  Somogyi  (Physiol.  Instit.,  Budapesth),  Zeitschr.  f.  physiol.  Chem., 
71,  125, 1911. 

78  P.  Rona  and  L.  Michaelis,  1.  c. 

78  U.  Friedemann  and  S.  Isaak,  1.  c. 

80 E.  Heilner  (Physiol.  Instit.,  Munich)  Zeitschr.  f.  Biol.,  58,  333,  1912;  cf. 
therein  Literature. 


PARENTERAL  FEEDING  WITH  SUGAR  511 

ministration  of  protein.  From  studies  in  this  connection  by 
Stolte,  Salaskin  and  Kowalewski,  Abderhalden  and  his  asso- 
ciates, and  from  those  of  Wohlgemuth,  but  particularly  from 
very  recent  investigations  in  Bottazzi's  laboratory,81  the 
results  clearly  indicate  that  aminoacids  injected  into  the 
blood  are  eliminated  only  in  a  small  fraction  by  way  of  the 
kidneys,  that  the  bulk  disappear  within  the  body,  and  that 
there  is  no  intrinsic  reason  why  we  should  not  attribute  to 
them  the  possibility  of  taking  part  in  the  up-building  of 
protein  in  the  system.  It  seems,  too,  that  aminoacids  can  be 
introduced  directly  in  the  veins  of  an  animal  in  quantities 
quite  sufficient  for  the  nitrogen  requirements  of  the  animal 
without  the  necessity  of  fearing  severe  toxic  phenomena. 
Our  experience  with  the  matter  is,  however,  as  yet  not 
extensive  enough  to  justify  a  final  opinion. 

The  ability  of  the  body  to  handle  parenterally  introduced 
proteins  is  explicable  from  the  investigations  of  Abderhalden 
and  his  collaborators,  who  have  shown  by  the  "optical 
method"  that  the  plasma  of  animals,  after  parenteral  injec- 
tion of  proteins  and  high  molecular  products  of  protein- 
cleavage,  possesses  the  power  to  catabolize  these  substances. 
It  seems  that  under  these  circumstances  the  formed  elements 
of  the  blood  and  other  body  cells  give  off  peptolytic  ferments, 
just  as,  according  to  Abderhalden  and  to  Heilner,  after 
parenteral  introduction  of  compound  carbohydrates  (as 
cane-sugar,  milk-sugar  and  starch)  ferments  appear  de  novo 
in  the  plasma  which  induce  cleavage  of  these  substances.82 

Parenteral  Feeding  with  Sugar. — What  may  be  accom- 
plished in  the  way  of  parenteral  nutrition  with  sugar? 

In  this  connection  attention  may  be  called  to  a  series  of 
very    interesting    observations    recently    collated    by    W. 

81  G.  Buglia  (F.  Bottazzi's  Lab.,  Naples),  Zeitschr.  f.  Biol.,  58,  162,  1912, 
and  earlier  studies;    cf.  therein  Literature. 

82  Abderhaldens  works  on  the  proof  of  proteolytic  and  peptolytic  ferments 
after  introduction  of  specifically  foreign  and  blood-foreign  proteins  and  peptones 
are  collected  in  Abderhalden^  Synthesis  der  Zellbausteine  (Berlin,  J.  Springer, 
1912),  pp.  119-120. 


512  PARENTERAL  NUTRITION 

Kautsch 83  upon  a  group  of  forty  persons.  Subcutaneous  in- 
jections of  grape-sugar  are  apparently  from  these  studies 
well  borne  up  to  five  per  cent,  strength ;  stronger  solutions 
occasion  pain.  So,  too,  intravenous  infusions  of  as  much 
as  1000.  cubic  centimetres  of  a  five  to  seven  per  cent,  solu- 
tion of  grape-sugar  are  remarkably  well  tolerated.  Only 
a  small  fraction  of  the  sugar  thus  incorporated  appears 
in  the  urine.  The  worse  the  state  of  general  nutrition  the 
greater  the  quantity  of  sugar  which  is  tolerated.  A  woman 
with  puerperal  sepsis,  peritoneal  symptoms,  vomiting  and 
diarrhoea,  received  each  day  for  six  days  a  solution  of  sugar, 
going  as  high  as  two  litres  a  day,  with  a  concentration  of  the 
solution  gradually  increasing  up  to  nine  per  cent. ;  she  re- 
covered. Kautsch  urges  that  intravenous  nourishment  with 
grape-sugar  be  tried  also  in  severe  hysterical  vomiting,  in 
serious  catarrhs  of  the  stomach  and  intestine,  as  well  as  in 
cholera.  Intraperitoneal  injections  of  a  five  per  cent,  solu- 
tion of  glucose  in  human  beings  give  rise,  according  to  A. 
Schmidt,  to  considerable  peritoneal  irritation.84 

It  was  formerly  thought  that  cane-sugar,  when  intro- 
duced parenterally,  passes  entirely  into  the  urine ;  but,  ac- 
cording to  recent  investigations  by  E.  Heilner 83  and  by  L.  B. 
Mendel,80  this  is  by  no  means  the  case.  Thus,  if  one  to  two 
grams  pro  kilogram  of  body  weight  be  injected  into  cats  or 
dogs,  either  intravenously  or  ihtraperitoneally,  only  sixty- 
five  per  cent,  is  recoverable  in  the  urine.  As  above  stated, 
we  must  assume  that  there  occurs  a  fermentative  cleavage  of 
the  disaccharide  in  the  blood  (perhaps  by  a  protective  fer- 
ment formed  ad  hoc).     After  parenteral  introduction  of 

83  W.  Kautsch  ( Augusta- Victoria  Hospital,  Berlin-Schüneberg),  Deutsch, 
med.  VVochenschr.,  1911,  8. 

**A.  Schmidt  and  H.  Meyer  (Dresden),  Deutsch.  Arch.  f.  klin.  Med.,  85, 
119,  1905. 

85 E.  Heilner  (O.  Frank's  Lab.,  Munich),  Zeitschr.  f.  Biol.,  56,  75,  1911. 

88 L.  B.  Mendel  and  J.  J.  Kleiner  (Yale  Univ.,  New  Haven),  Amer.  Jour  of 
Physiol.,  26,  396,  1910. 

87 L.  B.  Mendel  and  P.  H.  Mitchell  (Yale  Univ.),  Amer.  Jour,  of  Physiol., 
Ik,  239,  1905. 


PARENTERAL  FEEDING  WITH  FAT  513 

glycogen  there  may  be  found  in  the  urine  a  body  similar  to 
achroodextrin.87  Soluble  starch  appears  in  the  urine  if 
injected  rapidly  but  does  not  appear  if  gradually  introduced ; 
it  evidently  undergoes  conversion  into  sugar  in  the  blood.88 
Parenteral  Feeding  with  Fat. — Finally  what  of  paren- 
teral nutrition  by  fat?  It  has  been  stated  in  connection 
with  the  discussion  of  fat  metabolism  that  the  subcutaneous 
introduction  of  fat  as  a  nutrient  as  recommended  by  Leube 
has  not  been  approved  in  practice,  and  cannot  be  maintained, 
because  it  turns  out  that  olive  oil,  introduced  drop  by  drop, 
is  absorbed  from  the  subcutaneous  tissue  so  very  gradually, 
that  only  a  few  grams  can  be  absorbed  in  the  course  of  a 
day.89  However  it  appears  that  these  failures  have  been 
due  entirely  to  the  faulty  methods  of  introduction.  Intra- 
peritoneal absorption  of  injected  fats  takes  place  very  rap- 
idly in  man  and  the  lower  animals ;  and  it  may  be  added  that 
the  oil  injections  have  a  less  irritative  effect  than  either 
sugar-  or  protein-solutions.90  However  even  from  the  sub- 
cutaneous tissue  resorption  of  oil  takes  place  when  it  is  emul- 
sified with  lecithin  and  water,  apparently  rapidly  enough  for 
the  economy  to  obtain  in  this  way  at  times  from  half  to  three- 
fourths  of  its  required  calories.91  It  is  quite  likely  that 
medical  practice  of  the  future  will  have  to  reckon  with  these 
hitherto  insufficiently  regarded  subjects. 

88  F.  Verzär   (Tangl's  Lab.),  Biochem.  Zeitschr.,  34,  66,  1911. 

89  H.  Winternitz,  Zeitschr.  f.  Min.  Med.,  50,  80,  1903;  Yandell  Henderson 
and  E.  F.  Crofutt,  Amer.  Jour,  of  Physiol.,  14,  193,  1905;  E.  Heilner,  Zeitschr. 
f.  Biol.,  5Jf,  54,  1910. 

J0  A.  Schmidt  and  H.  Meyer,  1.  c. 

91  L.  H.  Mills,  Arch.  int.  Med.,  7,  694,  1911.  cited  in  Centralbl.  f.  d.  ges.  Biol., 
1911,  No.  2902. 


33 


CHAPTER  XXI 

METHODS  OF  STUDY  OF  GAS  EXCHANGE.  MAIN- 
TENANCE METABOLISM  AND  GROWTH.  ENERGY 
EXCHANGE  AFTER  INGESTION  OF  FOOD 

In  the  course  of  these  lectures  reference  has  frequently 
been  made  to  estimation  of  the  volume  of  gas  exchange,  of 
the  respiratory  quotient  and  similar  matters.  An  explana- 
tion of  the  methods  which  we  have  at  our  disposal  for  de- 
termining these  values  has,  however,  not  been  presented,  and 
the  opportunity  should  be  taken  at  this  time  to  repair  this 
neglect,  by  at  once  outlining  the  technic  of  the  modern  study 
of  gaseous  metabolism 1  as  fully  as  seems  to  pertain  to  gen- 
eral biochemical  training. 

METHODS  OF  GAS  EXCHANGE  STUDIES 

PettenJcofer  Type  of  Respiration  Apparatus. — A  respira- 
tion experiment  may  be  conducted  on  Pettenkofer 's  principle 
by  placing  the  individual  concerned  in  an  enclosed  space 
through  which  a  current  of  air  is  passed  by  a  pump  mechan- 
ism. The  volume  of  the  air  is  measured  by  means  of  a  gas- 
meter,  and  an  aliquot  portion  is  analyzed  for  its  water  and 
carbonic  acid  by  means  of  sulphuric  acid-  and  baryta-re- 
ceivers. The  respiration  apparatus  of  Sonden  and  Tiger- 
stedt,  the  respiration  chamber  of  which,  a  room  lined  with 
sheet  zinc,  is  large  enough  to  accommodate  a  number  of  per- 
sons at  the  same  time,  works  on  this  principle;  but  the  gas 
samples  from  it  are  analyzed  by  a  volumetric  method.  The 
method  is  very  exact,  the  error  in  carbonic  acid  (as  shown  by 
control  experiments  in  which  known  amounts  of  oil  were 

1  Literature  upon  Respiration  Apparatus :  A.  Jaquet,  Ergebn.  d.  Physiol., 
2,  458-462,  1902;  W.  O.  Atwater,  ibid.,  8,  498-512,  1904;  A.  Magnus-Levy, 
Handb.  d.  Pathol,  d.  Stoffw.,  2d  ed.,  1,  198-212,  1906;  A.  Loewy,  Handb.  d. 
Biochem.,  4',  133-144,  1908;  0.  Cohnheim,  Physiol,  d.  Verdauung  und  Ernäh- 
rung, pp.  360-365,  1908. 

514 


TYPES  OF  RESPIRATION  APPARATUS  515 

burned)  being  scarcely  greater  than  two  per  cent.    Jaquet's 
respiration  apparatus  is  based  upon  the  same  principle. 

Regnault  and  Reiset  Type  of  Respiration  Apparatus. — 
The  principle  of  reneAval  of  a  circulating  current  under- 
lies the  respiration  apparatus  of  Begnault  and  Reiset,  in 
which  the  same  body  of  air  after  having  its  carbonic  acid 
removed  is  constantly  repassed  through  the  respiration 
chamber,  the  oxygen  being  renewed  from  a  gas  reservoir  as 
required.  Although  in  its  original  form  this  apparatus  was 
only  suited  for  the  study  of  small  animals,  Hoppe-Seyler  con- 
structed a  form  on  the  same  principle,  the  respiration  cham- 
ber of  which  afforded  continuous  accommodation  for  a  hu- 
man being,  being  of  about  five  cubic  metres  dimension.  A 
more  capacious  and  very  much  more  satisfactory  type  on  the 
same  principle  may  be  seen  in  the  large  respiratory  ap- 
paratus constructed  by  N.  Zuntz  and  C.  Oppenheimer,  in  the 
Physiological  Institute  of  the  Agricultural  High  School  in 
Berlin,  with  a  capacity  of  eighty  cubic  metres.  A  tread  mill, 
enabling  the  performance  of  desired  movements  uphill  and 
downhill  as  well  as  exactly  prescribed  traction,  is  built  in. 
Moreover  the  trachea  of  an  enclosed  animal  can  be  connected 
by  conducting  tubes  with  measuring  apparatus  so  that 
separate  study  of  pulmonary  breathing  and  gas  exchange 
through  the  skin  and  intestine  can  be  carried  on.  By  means 
of  special  provisions  the  apparatus  makes  it  possible  to  have 
any  desired  temperature,  atmospheric  moisture  and  (by  fans ) 
also  any  atmospheric  movements  act  upon  human  beings, 
to  make  changes  in  the  proportions  of  oxygen  and  carbonic 
acid  in  the  air,  and  thus  in  some  degree  to  produce  artifi- 
cially any  sort  of  climate.  The  apparatus  can  be  arranged 
for  employment  on  Pettenkofer's  principle  as  well  as  on 
that  of  Regnault  and  Reiset.  Ordinarily  it  is  used  in  the 
latter  manner,  and  the  air  for  respiration  purposes  is  chilled 
in  a  tower  seven  metres  high  from  contact  with  a  system 
of  cooling  pipes  down  to  a  temperature  of  — 10°  C,  and  ex- 


516  METHODS  OF  GAS  EXCHANGE  STUDIES 

exposed  to  a  shower  of  caustic  potash,  being  thus  freed  thor- 
oughly of  its  moisture  and  carbonic  acid.  In  the  Children's 
Clinic  in  Düsseldorf  there  is  a  similar  apparatus  arranged 
for  the  study  of  the  gas  metabolism  of  infants.  Control  ex- 
periments with  combustion  of  alcohol  in  this  apparatus  have 
shown  an  average  error  of  0.4  per  cent,  in  carbonic  acid 
determination,  which  is  to  be  regarded  as  a  very  remarkable 
performance.2 

Respiration  Calorimeter  of  Atwater  and  Benedict. — The 
apparatus  of  the  American  physiologists,  Atwater  and 
Benedict,  is  undoubtedly  to  be  regarded  as  the  most  com- 
plete thus  far  constructed  for  the  study  of  the  respiratory 
and  general  metabolism.  The  respiration  chamber  of  this 
apparatus  is  a  room  provided  with  a  table,  bed  and  folding 
chair  in  which  the  experiment  subject  may  eat,  drink,  sleep, 
work  and  remain  for  days.  The  room  is  surrounded  by  a 
double  layer  of  air,  there  being  three  walls.  There  is  in- 
cluded a  system  of  water  pipes,  very  much  like  a  hot  water 
system  of  heating,  which  takes  away  any  excess  of  heat; 
knowing  the  amount  of  water  which  passes  through  the 
apparatus  in  the  course  of  the  experiment  and  the  amount 
of  heat  it  acquires  in  passage,  the  total  amount  of  heat  pro- 
duced can  be  readily  determined.  There  are,  however,  ar- 
ranged in  the  walls  about  the  respiration  chamber  ther- 
mometers and  a  system  of  wiring  for  electrical  heating.  The 
thermometers  are  connected  with  a  galvanoscope,  the  steadi- 
ness of  which  is  assurance  of  the  constancy  of  the  tempera- 
tures during  the  experiment.  An  attendant  keeps  the  gal- 
vanoscope constant  throughout,  correcting  for  the  least  vari- 
ation, either  by  altering  the  current  of  water  circulating 
through  the  walls  or  by  the  electrical  heating  appliance.  It 
is  not  difficult  to  keep  the  current  of  air  even  in  temperature 
in  this  way  from  the  time  of  its  admission  to  its  exit  from 

2  Züntz  and  C.  Oppenheimer,  Biochem.  Zeitschr.,  l'f,  361,  1908;  A 
Schlossmann,  C.  Oppenheimer  and  H.  Murschhauser,  ibid. 


METHOD  OF  ZUNTZ  AND  GEPPERT  517 

the  apparatus.  Tests  are  made  before  and  after  in  order  to 
determine  exactly  the  amounts  of  carbonic  acid  and  water 
given  off  from  the  body  by  the  lungs  and  skin.  Proper  pro- 
visions are  made  for  the  introduction  of  food  and  drink  and 
the  removal  of  the  solid  and  fluid  excreta.  These  are 
analyzed,  not  only  for  nitrogen,  fat,  carbohydrate  and  inor- 
ganic constituents,  but  also  (by  means  of  a  calorimeter 
bomb)  for  their  combustion  temperature,  thus  providing  all 
conditions  for  a  complete  report  of  the  energy  exchange  and 
metabolism.  The  reliability  of  the  apparatus  is  determined 
for  control  purposes  at  the  beginning  and  at  the  end  of  each 
experiment  by  burning  in  it  an  exactly  known  quantity  of 
alcohol.  As  evidence  of  the  precision  attained  with  the 
apparatus  it  may  be  added  that  in  the  alcohol  experiments 
the  average  results  for  three  years  show  the  recovery  of  100 
per  cent,  of  the  theoretically  calculated  quantities  of  carbon 
dioxide,  103.1  per  cent,  of  the  water,  and  100.2  per  cent,  of 
the  heat.3  Such  results  are  magnificent  and  marvelous,  and, 
uninteresting  as  they-may  sound,  may  well  make  the  heart  of 
every  friend  of  exact  nature-study  beat  higher. 

Method  of  Zuntz  and  Geppert. — The  great  strides  in  the 
study  of  metabolism  would  have  been  impossible,  however,  if 
the  results  obtained  by  these  bulky,  costly  and  complicated 
apparatuses  just  described  were  not  supplemented  by  the 
device  of  Zuntz  and  Geppert.  The  individual  experimented 
upon  in  this  case  inhales  atmospheric  air  through  a  mouth- 
piece, and  the  volume  of  expired  air  is  measured  by  a  gas 
meter ;  the  separation  of  the  inspired  and  exhaled  air  being 
accomplished  by  a  suitable  valve.  A  small  portion  of  the 
exhaled  air  is  automatically  taken  up  from  time  to  time  and 
analyzed  volumetrically  in  two  burettes.  Besides  the  per- 
manent form  of  the  apparatus  Zunz  also  devised  a  portable 
form,  adapted  to  studies  in  travel,  mountain  trips  and  at  the 

3  Atwater,  1.  c,  p.  514. 


518  METHODS  OF  GAS  EXCHANGE  STUDIES 

sick  bed.  This  method  is  only  suited  for  brief  experiments 
(minutes  up  to  several  hours),  particularly  in  determining 
the  effect  of  muscular  effort,  individual  nutrient  materials 
and  medicinal  agents,  etc.,  but  not  for  estimating  the  metab- 
olic exchange  over  longer  periods.  Magnus-Levy  4  expresses 
the  following  opinion  of  the  Zuntz  method :  "For  exact  meas- 
urement of  the  actual  exchange  for  a  whole  day  or  longer 
the  twenty-four  experiments  are  absolutely  authoritative. 
Only  from  them  can  we  learn  to  practically  realize  the  nutri- 
tional requirements,  etc. ;  they  constitute  the  exact  basis  for 
quantitative  consideration  of  scientific  and,  too,  practical 
questions  in  nutrition.  The  method  makes  it  possible  to 
fully  collate  all  the  influences  bearing  upon  metabolism. 
However,  it  is  not  so  well  adapted  for  the  precise  determina- 
tion of  the  value  of  each  individual  external  factor.  Where 
it  is  essential  to  have  as  sharp  differentiation  and  determina- 
tion as  possible  of  such  influences  experiments  of  short  dura- 
tion are  of  more  significance,  and,  because  of  their  readier 
technic,  have  come  to  occupy  a  very  much  greater  field. 
This  is  especially  true  where  one  is  dealing  with  the  estima- 
tion of  relatively  small  differences." 

Other  Methods. — Among  other  forms  of  apparatus  de- 
signed for  the  measurement  of  gas  interchange  may  be  men- 
tioned the  head  respiration  apparatus  of  E.  Gräfe,5  which  is 
snugly  adjusted  by  means  of  an  inflatable  rubber  collar ;  also 
a  new  transportable  respiration  apparatus  of  Benedict;0 
and,  lastly,  a  device  of  Douglas,  in  which  the  exhaled  air  is 
collected  in  a  bag  which  the  subject  carries  on  his  back,  and 
after  the  close  of  the  experiment  analyzed. 

Recent  forms  of  respiration  apparatus  satisfying  modern 
requirements  and  used  for  small  animals  have  been  con- 

4  A.  Magnus-Levy,  1.  c,  p.  212. 

5E.  Gräfe  (Med.  Clin.,  Heidelberg),  Deutsch.  Arch.  f.  klin.  Med.,  95,  529, 
1909;    cf.  also  Zeitschr.  f.  physiol.  Chem.,  65,  1,  1910. 

6  F.  G.  Benedict  (Carnegie  Lab.,  Boston),  Amer.  Jour,  of  Physiol.,  2Jf,  345, 
1909. 


OTHER  TYPES  OF  APPARATUS  519 

structed  by  H.  Murschhauser,7  H.  B.  Williams 8  and  F. 
Tangl.9 

Studies  of  the  gas  exchange  of  aquatic  animals  require  a 
special  technic,  elaborated  for  observations  on  fish  by 
Zuntz,  in  association  with  Knauthe  and  Cronheim,10  for 
lower  marine  organisms  by  Jolyet  and  Regnard  and  by 
Vernon.11 

In  conclusion  the  writer  must  not  neglect  to  refer  to  the 
great  importance  of  Rubner's  calorimeter  in  the  develop- 
ment of  metabolic  study;  this  relatively  simple  apparatus 
must  be  credited,  too,  with  a  number  of  very  important  dis- 
coveries, which  may  be  offered  as  proof  that  in  physiology 
often  far  more  is  attained  through  judicious  proposals  of 
problems  and  precise  and  skillful  performance  of  work 
than  by  elaborate  and  costly  apparatus.12  On  the  other  hand 
the  study  of  metabolism  itself  teaches  us  that  without  a  cer- 
tain minimum  of  auxiliary  means  and  power  and  the  nervus 
rerum  requisite  for  procuring  them,  even  the  best  arrange- 
ment of  researches  must  remain  without  result  and  the  most 
industrious  hands  without  a  task.  The  prime  point  in  the 
mechanical  theory  of  heat,  which  has  been  occasionally  cited 
in  these  lectures  in  its  popular  rendering  ("from  nothing, 
nothing  comes ' ') ,  is  applicable  as  well  in  the  modern  study  of 
metabolism.  Just  here  the  old  hemisphere  can  learn  much 
from  the  new.  Yet  if  unfortunately  we  are  unable  to  bring 
into  existence  a  Carnegie  Institution  or  a  Rockefeller  Insti- 
tute, a  very  great  deal  can,  nevertheless,  be  done  in  biochem- 
istry with  more  modest  means. 

7  H.  Murschhauser  (Acad.  Pediatric  Clinic,  Düsseldorf),  Biochem.  Zeitschr., 
42,  262,  1912. 

8H.  B.  Williams  (Cornell  Univ.,  New  York),  Jour,  of  Biol.  Chem.,  12, 
317,  1912. 

9F.  Tangl  (Budapesth),  Biochem.  Zeitschr.,  U,  235,  1912. 

10  W.  Cronheim,  Zeitschr.  f.  Fischerei,  15,  319,  1911;  separate  pub.  by  Born- 
träger Brothers,  Berlin. 

"Literature  on  Respiration  of  Aquatic  Animals:  O.  v.  Fürth,  Vergl.  chem. 
Physiol,  der  niederen  Tiere,  pp.  121-130,  Jena,  1903. 

12  O.  Cohnheim,  1.  c,  p.  363. 


520        MAINTENANCE  EXCHANGE  AND  GROWTH 

Question  of  Part  Taken  by  Elemental  Nitrogen  and 
Hydrogen  in  Metabolism. — The  advances  in  technique  of 
respiration  investigation  have  done  away  with  the  old  sub- 
ject of  debate  as  to  the  part  taken  by  nitrogen  as  an  element 
in  the  processes  of  metabolism.  The  final  proof  that  no  nitro- 
gen in  free  condition  is  ever  eliminated  from  the  body  and 
that  the  statements  to  the  contrary  by  other  authors  are  due 
to  errors  of  observation  has  been  attained  through  the  care- 
ful investigations  of  Carl  Oppenheimer  13  and  of  Krogh.14 
Oppenheimer  was  able  to  show,  too,  that  elemental  hydro- 
gen has  just  as  little  to  do  with  metabolism  as  does  nitrogen, 
and  that  even  when  in  high  tension  in  the  blood  hydrogen 
does  not  undergo  combustion  in  metabolism.15  Ammonia, 
which  is  occasionally  met  in  exhaled  air,  to  all  appearances  is 
due  merely  to  processes  of  decomposition  going  on  in  the 
mouth  and  bronchial  tubes.16 

MAINTENANCE  EXCHANGE  AND  GROWTH 

The  possibility  of  continuing  respiration  experiments  on 
human  beings  for  a  very  long  time  and  under  nearly  normal 
conditions  makes  it  also  possible  to  determine  the  exchange 
taking  place  in  maintenance.  A.  Löwy  states :  "  By  the  term 
maintenance  exchange  may  be  understood  that  basic  volume 
of  metabolism  which  (excluding  those  tissue  activities  pro- 
viding for  transient  requirements  or  producing  extra  ef- 
forts) is  essential  for  the  maintenance  of  the  continuous  vital 
functions.  The  maintenance  metabolism  of  every  adult  in- 
dividual presents  a  constant  volume  which  remains  uniform 
for  years  and  decades  of  years,  as  long  as  the  body  char- 
acteristics of  the  individual  do  not  become  changed  to  an 

13  C.  Oppenheimer  (Zuntz's  Lab.,  Berlin),  Biochem.  Zeitschr.,  1,  177,  1906; 
Jf,  328,  1907. 

14  A.  Krogh  (Copenhagen),  Sitzungsher.  d.  Wiener  Akad.,  115'",  1906;  cf. 
therein  Literature. 

16  C.  Oppenheimer  (Zuntz's  Lab.,  Berlin),  Biochem.  Zeitschr.,  16,  45,  1908. 
16  Literature  upon  the  Composition  of  Exhaled  Air :    A.  Jaquet,  Ergebn.  d. 
Physiol.,  2,  463-468,  1902;   A.  Löwy,  ibid.,  -'/',  144-154,  1908. 


IMPORTANCE  OF  SURFACE  DEVELOPMENT        521 

important  degree."  17  To  determine  the  maintenance  ex- 
change (minimal  metabolism)  1S  it  is  obvious  that  complete 
body  rest  and  a  state  of  fasting  are  essential.  Reference 
has  been  made  repeatedly  to  the  fact  that  any  sort  of  mus- 
cular activity  increases  exchange  in  a  marked  degree. 
Johannson  recognizes  three  types  of  "rest":  complete  en- 
forced rest,  rest  in  bed,  and  rest  in  the  room,  in  the  last  of 
which  there  may  be  permitted  alternation  of  quiet  sitting, 
reading,  writing  and  other  light  occupations.  It  is  very 
instructive  to  note  that  the  exchange  in  rest  in  bed  is  upwards 
of  twenty  per  cent.,  and  in  rest  in  the  room  fifty  to  sixty  per 
cent,  higher  than  that  in  enforced  rest.  It  may  thus  be  per- 
ceived that  the  actual  determination  of  the  maintenance  ex- 
change is  by  no  means  an  easy  task.  It  is  essential  to  ex- 
clude not  only  the  activity  of  the  striated  musculature  but 
also  that  of  the  involuntary  muscle  of  the  gastrointestinal 
canal,  and  of  that  of  the  periodically  acting  glands  as  well. 
That  this  is  not  possible  in  a  literal  sense  of  course  goes 
without  stating ;  we  do  the  best  we  can,  and  are  careful  to 
determine  the  gas  exchange  in  a  period  of  fasting,  about 
twelve  hours  after  the  last  meal,  in  a  restful  posture,  and 
with  most  careful  avoidance  of  all  voluntary  movements. 
The  fact  is,  however,  that  for  one  and  the  same  person 
under  these  conditions,  in  the  course  of  many  years,  exactly 
the  same  oxygen  consumption  and  the  same  carbonic  acid 
production  are  usually  obtained  in  the  same  period  of  ob- 
servation.19    Sleeping  or  waking  play  no  important  part. 

Significance  of  Surface  Development  and  Volume  of 
Body  Protein. — It  will  be  readily  appreciated  that  in  com- 

17  A.  Löwy,  Handb.  d.  Biocliem.,  Jf' ,  172,  1908. 

18  Literature  upon  Maintenance  Exchange:  A.  Magnus-Levy,  Handb.  d. 
Pathol,  d.  Stofl'w.,  2d  ed.,  1,  213,  222-225,  279-296,  190G;  A.  Löwy,  Handb.  d. 
Biochem.,  4',  172-199,  1908. 

19 Thus,  for  example,  A.  Löwy  (Deutsche  med.  Wochenschr.,  1910,  1797) 
observed  in  an  experiment  subject  at  absolute  rest  and  during  fasting  the 
following  oxygen  consumption  (cubic  cm.  pro  minute)  :  in  1888,  23G.0;  in 
1895,  227.9;    in  1901,  230.7;    in  1902,  238.1;    in  1903,  228.0. 


522         MAINTENANCE  EXCHANGE  AND  GROWTH 

parison  of  different  individuals  the  determination  of  the 
maintenance  metabolism  will  give  different  numerical  values, 
which  will  not  harmonize  well  if  we  base  our  results  on  the 
unit  of  body  weight.  It  does  not  depend  so  much  upon  the 
size  of  the  body  as  upon  the  amount  of  active  protoplasm  in 
particular.  A  strong  muscular  individual  will  consume 
more  energy  than  one  of  equal  weight  in  whom  the  muscula- 
ture is  replaced  by  the  dead  weight  of  large  fat  deposits. 
The  surface  development,  however,  as  correctly  recognized 
by  C.  Bergmann  about  the  middle  of  the  past  century,  but 
first  actually  proved  by  Rubner,  is  a  matter  of  great  impor- 
tance in  this  connection.  The  larger  the  surface  in  compari- 
son to  the  body  mass  the  greater  the  heat  elimination,  ceteris 
paribus;  and  the  greater  the  heat  loss,  necessarily  the 
greater  the  heat  production  must  be  to  maintain  constancy 
of  body  temperature.  As  small  individuals,  in  proportion 
to  their  body  volume,  have  a  greater  extent  of  surface,  they 
necessarily  produce  proportionately  a  greater  amount  of 
heat.  It  has  been  proved  in  many  cases  that  while  the  ratio 
between  exchange  and  body  weight  is  irregular,  almost  con- 
stant figures  are  obtained  if  the  amount  of  metabolism  is 
calculated  in  proportion  to  the  unit  of  body  surface.  There- 
fore there  can  be  no  question  as  to  the  importance  of  this 
factor.  Exclusive  emphasis  of  this  may,  however,  as  in 
case  of  any  one-sided  consideration,  miss  the  mark.  Rubner 
himself  proved  that  the  difference  between  the  exchange  in 
big  and  little  guinea  pigs  is  still  evident  if  heat  elimination 
is  excluded  by  providing  a  surrounding  temperature  of  30°. 
Moreover  an  analogous  difference  in  the  metabolism  of  cold- 
blooded animals  (fish),  in  which  temperature  regulation 
does  not  enter  at  all,  has  been  shown  by  Jolyet  and  Regnard, 
and  by  Knauthe.  E.  Voit  found  that  maintenance  exchange 
in  poorly  nourished  individuals  decreases,  independently  of 
the  body  surface,  with  loss  in  the  volume  of  body  protein. 


ENERGY  CALCULATION  IN  INFANCY  523 

From  these  facts  the  author  is  inclined  to  believe  (as,  too, 
from  the  objections  of  Zuntz  and  his  pnpils  and  those  of 
H.  Friedenthal  and  others)  that  we  may  conclude  that  main- 
tenance exchange  does  not  depend  merely  upon  the  surface 
area  of  the  body,  but  also,  and  in  very  distinct  manner,  upon 
the  amount  of  active  protoplasm,  and  doubtless  also  upon  a 
number  of  other  items  which  we  cannot  entirely  overlook.20 

The  female  sex  does  not  show  any  lower  activity  in  main- 
tenance metabolism  than  the  male ;  but  in  senility  there  is  a 
notable  diminution,  and  in  childhood  exchange  is  always 
distinctly  higher  than  in  adult  life,  whether  determined  in 
relation  to  body  weight  or  to  surface  area  of  the  body.  If 
the  amount  of  gas  interchange  in  a  man  be  taken  as  100, 
according  to  Magnus-Levy  and  Falck,  it  is  78  in  a  senile 
individual  and  in  the  child  it  may  reach  about  110. 

Energy  Calculation  in  Infancy. — Special  attention 
should  be  devoted  to  the  energy  calculation  in  infancy.  The 
infant's  exchange  is  peculiar  in  that,  even  when  determined 
for  the  surface  unit,  it  is  decidedly  low  during  the  first  month 
of  life,  and  only  reaches  by  a  gradual  rise  the  level  char- 
acteristic of  childhood  about  the  end  of  the  third  month.21 
The  method  of  energy  computation  introduced  by  Camerer 
into  the  study  of  child  nutrition  has  since  come  to  be  a  mat- 
ter of  considerable  consequence  to  pediatrists.  Heubner  and 
Rubner  have  attempted  to  systematize  the  matter  of  energy 
recording  in  infants,  deducting  from  the  ' '  native  calories ' ' 
of  the  food  the  number  of  calories  lost  in  the  faeces  and  urine 
and  thus  arriving  at  the  "net  calories"  which  are  actually 
available  to  the  infant.  By  dividing  the  number  of  native 
calories  introduced  into  the  body  by  the  body  weight  Heub- 
ner's  energy-quotient  is  obtained,  which  refers  to  the  num- 

20  Cf.  A.  Löwy,  Handb.  d.  Biochem.,  i ',  186,  1908;  H.  Friedenthal  (Lake 
Nicholas,  Berlin),  Centralbl.  f.  Physiol.,  23,  437,  1909;  J.  Howland  (Graham 
Lusk's  Lab.,  New  York),  Zeitschr.  f.  physiol.  Chem.,  lit,  1,  1911. 

a  Cf.  A.  Löwy,  Handb.  d.  Biochem.,  4',  P-  189,  1908. 


524        MAINTENANCE  EXCHANGE  AND  GROWTH 

ber  of  calories  a  child  must  receive  daily  pro  kilogram  in 
order  to  develop  satisfactorily.  According  to  Heubner's 
views  a  breast-fed  child  is  able  to  store  up  more  reserve 
power  than  an  artificially  fed  child.  Extensive  computa- 
tion experiments  have  been  carried  out  in  the  laboratories  of 
Tangl  and  of  Zuntz ;  energy  observations  bearing  upon  food 
requirements  of  the  infant  have  been  made  by  A.  Czerny  and 
his  pupils,  as  well  as  by  a  very  large  number  of  pediatrists. 
Direct  measurements  of  maintenance  metabolism  have  been 
carried  out  within  the  last  year  or  two  especially  by  Schloss- 
mann, in  Düsseldorf,  by  means  of  the  above  described 
respiration  apparatus  with  due  conformity  to  all  modern 
requirements.  The  infants  are  quieter  than  one  would  ex- 
pect in  the  respiration  experiments  and  tolerate  well  even 
rather  long  fasting.  In  this  way  the  production  of  C02 
and  oxygen  consumption  were  found  to  be  dependent  not 
upon  the  age,  but  primarily  upon  the  surface  area.22 

Laws  of  Growth. — In  addition  attention  has  been  given 
to  the  application  of  the  method  of  energy  observation  to 
the  study  of  growth.  In  a  previous  lecture  (Vol.  I  of  this 
series,  p.  376,  Chemistry  of  the  Tissues)  reference  was  made 
to  the  credit  due  especially  to  Tangl  and  his  collaborators 
for  their  efforts  to  determine  the  developmental  work  neces- 
sary to  the  building  up  of  the  embryo. 

In  relation  to  the  growth  of  the  child,  C.  Oppenheimer 
was  the  first  to  call  attention  to  the  fact  that  if  the  acces- 
sions in  weight  of  breast-fed  children  of  even  age  be  com- 
pared, there  will  be  found  a  direct  proportion  to  the  amount 
of  milk  ingested.    Later  on  it  was  shown  in  Graham  Lusk's 

22  Literature  upon  Energy  Computation  in  the  Child :  L.  Langstein,  Ergehn. 
d.  Physiol.,  4,  851-890,  1905;  A.  Czerny  and  F.  Steinitz,  Handh.  d.  Pathol,  d. 
Stoflw.,  2d  ed.,  1,  441-445,  1907;  E.  Müller  (Zuntz's  Lab.),  Biochem.  Zeitschr., 
5,  193,  1907;  F.  Tangl  (Budapesth),  Pfliiger's  Arch.,  10k,  453,  1904;  M.  Rubner 
and  O.  Heubner,  Zeitschr.  f.  exper.  Pathol.,  1,  1,  1905;  P.  Reyher  (Berlin), 
Jahrb.  f.  Kinderheilk.,  61,  553,  1905;  A.  Schlossmann  and  H.  Murschhauser 
(Düsseldorf),  Biochem.  Zeitschr.,  26,  14,  1910. 


RUBNER'S  LAWS  OF  GROWTH  525 

laboratory  that  the  growth  of  pigs  runs  parallel  with  the 
value  in  calories  of  the  ingested  food ;  and  analogous  results 
were  obtained  by  Rost  in  case  of  young,  growing  dogs  of  the 
same  litter,  fed  on  meat,  fat  and  bone-ash.23  Rubner  has 
succeeded  by  his  careful  and  systematic  studies  in  formulat- 
ing certain  rules  characterizing  the  energetics  of  growth. 
First,  the  law  of  constant  consumption  of  energy,  an 
expression  of  the  observation  that  the  number  of  calories 
necessary  to  double  the  weight  of  a  newly  born  individual 
(horse,  cow,  sheep,  pig,  dog,  cat,  rabbit),  in  spite  of  the 
enormous  difference  in  time  consumed  in  attaining  the 
doubled  weight,  is  practically  the  same  for  all  species, 
reckoned  upon  the  unit  of  weight.  The  building  up  of  one 
kilogram  of  body  substance  requires  about  4800  calories.  An 
exception  is  met  in  the  case  of  man,  in  whom  about  six  times 
this  amount  is  required.  Man  is  exceptional  in  that,  while 
in  the  animals  enumerated,  of  one  hundred  net  calories  in- 
troduced about  thirty-four  are  fixed  (quotient  of  growth  = 
34),  human  beings  are  able  to  retain  only  about  five.  From 
the  law  of  constant  consumption  of  energy  it  follows  that  the 
shorter  the  period  of  development,  the  more  actively  must 
the  energy-metabolism  take  place.  As,  however,  the  amount 
of  the  latter  is,  in  accordance  with  Rubner 's  views,  to  be  re- 
garded as  a  function  of  the  surface  area,  we  arrive  at  the 
conclusion  that  the  smaller  the  animals  the  more  rapidly 
must  they  grow.  Rubner  has,  however,  also  attempted  to  de- 
duce a  rule  covering  the  length  of  life.  He  calculated  the 
amount  of  energy  which  is  consumed  in  a  kilogram  of  living 
protoplasm  from  the  stage  of  full  development  to  death,  and 
found  this  again  constant  for  all  domestic  animals  under  in- 
vestigation. But  here,  too,  man  occupies  an  exceptional  posi- 
tion, as  human  protoplasm  is  said  to  possess  the  capacity  of 

23  C.  Opppenheimer,  Zeitschr.  f.  Biol.,  Iß,  158,  1901 ;  M.  B.  Wilson,  Amer. 
Jour,  of  Physiol.,  8,  197,  1902;  E.  Eost,  Arb.  a.  d.  kaiserl.  Gesundheitsamt, 
18,  20G,  1902. 


526         MAINTENANCE  EXCHANGE  AND  GROWTH 

transforming  a  much  greater  amount  (about  quadruple)  of 
energy.24 

Flattering  as  this  exceptional  position  may  be  for  the 
members  of  the  species  Homo  sapiens,  a  uniformity  broken 
by  so  striking  an  exception  cannot  well  help  arousing  from 
the  very  outstart  serious  thoughts  as  to  the  validity  of  the 
law  itself.  From  observations  made  in  Zuntz's  laboratory 
by  Gerhartz  it  would  seem  that  the  maintenance  require- 
ment for  the  growing  dog  is  not,  as  Eubner  has  it,  simply  a 
function  of  the  surface  area;25  and,  more  particularly,  H. 
Friedenthal  has  brought  forward  a  series  of  observations 
which  in  general  do  not  conform  to  Eubner 's  laws  of 
growth.26  It  will  probably  be  in  every  way  more  valuable 
if,  instead  of  stating  his  own  opinion  upon  the  subject,  the 
author  presents  the  judgment  of  N.  Zuntz,  one  of  the  best 
authorities  upon  the  physiology  of  metabolism:  "The 
views  of  Eubner  as  to  the  remarkably  uniform  amount  of 
energy  (except  in  case  of  man)  consumed  by  an  organism  in 
course  of  growth  to  double  its  weight  are  in  the  meantime 
shaken  by  the  discoveries  of  Friedenthal,  and  man  forced 
from  the  special  position  which  seemed  to  belong  to  him. 
And  it  is  impossible  to  suppress  considerable  doubt  as  to  the 
validity  of  the  idea  that  living  matter  after  transforming  a 
given  number  of  calories  is  incapable  of  further  activity,  and 
that,  therefore,  death  naturally  ensues  when  a  certain  num- 
ber of  calories  per  kilogram  of  bodyweight  have  been  con- 
verted.   But  the  way  these  conceptions  were  developed  is 

24  M.  Rubner,  Arch.  f.  Hygiene,  66,  1908;  Das  Problem  der  Lebensdauer 
und  seine  Beziehungen  zu  Wachstum  und  Ernährung,  1908;  Kraft  und  Stoff 
im  Haushalt  des  Lebens,  Leipzig,  Akad.  Verlagsanstalt,  1909.  Rubner  has  re- 
cently (Sitzungsber.  d.  preuss.  Akad.,  1911,  440)  taken  up  the  question  of  the 
ratio  of  wear.  It  has  been  calculated  that  on  full  nitrogen-free  diet  about  one- 
thousandth  of  the  total  nitrogen  supply  of  the  body  is  daily  eliminated  in  the 
urine  and  faeces,  so  that  in  the  course  of  a  few  years  a  complete  renewal  of 
all  tissues  must  necessarily  take  place. 

25 H.  Gerhartz  (N.  Zuntz's  Lab.),  Biochem.  Zeitschr.,  12,  97,  1908. 

26  H.  Friedenthal,  Berliner  physiolog.  Gesellsch.,  June  3,  1910;  Centralbl.  f. 
Physiol.,  21f,  705,  1910;    cf.  also  the  rejoinder  by  Rubner. 


.  PHYSIOLOGICAL  UTILIZATION  VALUE  527 

full  of  suggestions  for  every  one  trained  in  natural  sci- 
ence. ' ' 27  The  author  believes  that  Eubner  's  efforts  will  be 
by  no  means  in  vain,  and  will  surely  be  of  use  in  the  solution 
of  the  problem  of  growth ;  although  perhaps  it  will  be  many 
decades  before  the  vast  material  from  observation  upon  the 
various  forms  of  life  can  be  collected  and  placed  upon  a 
broad,  comparative-physiological  basis,  so  as  to  enable  us 
hereafter  to  take  up  the  deduction  of  generally  valid  laws. 

ENERGY  EXCHANGE   AFTER   INGESTION    OF    FOOD 

We  may  here  turn  our  attention  to  energy  exchange  after 
the  intake  of  nutrient  materials. 

If  the  body  is  to  remain  in  complete  (both  in  material 
and  in  energy)  equilibrium  after  the  ingestion  of  food, 
metabolism  must  proceed  in  accordance  with  an  equation 
which  Robert  Tigerstedt28  formulates  as  follows:  "Com- 
bustion heat  of  food  =  combustion  heat  of  the  urine  and 
faeces  -f-  heat  loss  from  evaporation  of  moisture,  carbonic 
acid  output,  conduction  and  radiation  -f-  heat  loss  from 
absorption  of  heat  by  ingesta  -f-  heat  loss  from  externally 
useful  work  not  restored  to  the  body  as  heat. ' ' 

Physiological  Utilization  Value. — In  attempting  to  get  a 
proper  insight  into  the  utilization  value  of  nutrient  material 
it  is  necessary  primarily  to  consider  that  the  full  energy 
value  in  calories  of  a  food  can  be  fully  realized  only  if  it  be 
completely  consumed  in  the  economy.  This  actually  takes 
place  in  case  of  the  fats  and  carbohydrates,  their  oxidation 
in  the  course  of  metabolism  continuing  to  their  transforma- 
tion into  carbonic  acid  and  water.  But  with  the  proteins  it 
is  different,  these  substances  not  being  entirely  burned  into 
carbonic  acid,  water,  nitrogen  and  sulphuric  acid;  their 
nitrogen  appearing  in  the  urine  in  the  form  of  urea  and  a 
number  of  other  organic  compounds.  Therefore  in  attempt- 
ing the  determination  of  the  physiological  availability  of 

CTN.  Zuntz,  Centralbl.  f.  d.  ges.  Biol.,  10,  No.  28,  1910. 
28  R.  Tigerstedt,  Handb.  d.  Biochem.,  -J",  1,  1910. 


528  ENERGY  EXCHANGE  AFTER  FOOD 

protein,  the  amount  of  energy  which  is  lost  in  the  urine 
and  faxes  must  be  deducted  from  the  total  energy  which  is 
obtained  by  burning  the  protein  in  a  calorimetric  bomb; 
and  in  case  exactness  is  important  there  must  also  be  sub- 
tracted the  swelling-  and  solution-heat  of  the  protein  and  the 
solution-  heat  of  the  dried  urinary  substance. 

In  an  experiment  of  Rubner 's  29  one  gram  of  muscle  pro- 
tein was  found  to  yield  directly  a  combustion  heat  of  5754.0 
small  calories;  of  which  185.4  calories  were  lost  with  the 
faeces  and  1094.5  calories  with  the  urine.  In  addition  28.8 
calories  were  taken  up  as  solution-  and  swelling-heat  of  the 
protein  and  21.5  calories  as  solution-heat  of  the  urinary  sub- 
stances. There  remained,  therefore,  4423.8  small  calories 
as  the  specific  physiological  utilization  value  of  one  gram  of 
protein.  Rubner  estimated  a  somewhat  smaller  value  for 
the  protein  of  the  ordinary  mixed  diet  of  man,  and  as  already 
stated,  proposed  the  following  standard  figures : 

1  g.  Protein  4.1  large  calories 

1  g.  Fat  9.3  large  calories 

1  g.  Carbohydrate  4.1  large  calories 

Slightly  different  standard  values  have  been  proposed  by 

Atwater  and  by  the  Zuntz  school  (protein,  4.31;   fat,  9.46 

starch,  4.18). 30 

The  exactness  of  these  values  is  shown  by  the  following: 
Rubner  determined  in  a  dog  the  heat  production  and  gas 
interchange.  From  analysis  of  the  latter  and  of  the  urine 
and  faeces  it  was  calculated  just  how  much  protein,  fat  and 
carbohydrate  were  actually  consumed,  and  how  much  heat, 
therefore,  the  animal  must  have  produced.  Comparison  of 
this  theoretically  computed  heat  production  with  direct  ob- 
servation of  heat  production  showed  an  almost  complete 
agreement  (a  difference  of  between  one-half  and  one  per 
cent.). 

29  Cited  by  F.  Tangl,  Ergebn.  d.  Physiol.,  3",  45,  1909. 

30  Cf.  Literature:    A.  Löwy,  Handb.  d.  Biochem.,  4',  280,  1908. 


WORK  OF  DIGESTION  529 

Range  of  Metabolic  Increase. — The  variations  of  metab- 
olism after  the  ingestion  of  a  given  food  have  been  followed 
to  the  end  of  its  effect;  and  it  has  been  shown  that  every 
intake  of  food  is  followed  by  a  rise  in  gas  exchange  usually 
ending  within  twelve  hours.  The  increase  in  the  in-take  of 
oxygen  and  in  the  production  of  heat  is  least  after  ingestion 
of  fat,  is  larger  in  case  of  carbohydrates,  and  greatest  in 
case  of  protein.  Magnus-Levy  observed  that  even  after  an 
intake  of  200  grams  of  butter  or  bacon-fat  the  consumption 
of  oxygen  rarely  went  beyond  the  amount  in  fasting  by  over 
ten  per  cent.,  but  after  eating  a  ration  of  bread  in  the  first 
hour  an  increase  of  33  per  cent,  above  the  fasting  level  may 
be  reached  in  the  oxygen  consumption.  After  a  meal  of 
meat  a.  marked  and  longer  increase  of  gas  interchange  is  to 
be  observed.  In  experiments  of  Johansson,  Landergren, 
Sonden  and  Tigerstedt  on  feeding  days  as  compared  with 
fasting  days  an  average  increase  of  thirty-five  per  cent,  was 
noted.  Rubner  determined  the  caloric  requirement  in  a  dog 
and  then  on  three  different  days  fed  the  animal  on  one  day 
exclusively  on  protein,  on  another  exclusively  on  fat,  and 
on  another  exclusively  on  carbohydrate,  the  amounts  being 
in  each  case  equivalent;  his  results  showed  on  the  protein 
day  an  increase  in  heat  output  of  19.7  per  cent. ;  on  the  fat 
day,  6.8  per  cent. ;  on  the  carbohydrate  day,  10.2  per  cent.31 

The  question  next  arises  how  this  increase  in  metab- 
olism is  to  be  interpreted. 

Work  of  Digestion. — In  Speck's  opinion,  as,  too,  in  that 
of  Mering  and  Zuntz,  this  rise  in  metabolism  is  not  due  to 
combustion  of  the  resorbed  material  but  rather  to  the  work 
of  digestion,  this  including  not  only  the  work  of  the  mus- 
culature of  the  gastrointestinal  tract  but  also  the  heightened 
demands  of  the  collective  glandular  apparatus  connected 
therewith ;  and  in  addition  the  increased  cardiac  and  respir- 
atory activity  must  also  be  taken  into  consideration.    There 

81  Cf.  A.  Jaquet,  Ergebn.  d.  Physiol.,  2',  478-486,  1908. 
34 


530  ENERGY  EXCHANGE  AFTER  FOOD 

cannot  be  any  doubt  but  that  an  important  part  of  the  in- 
crease in  gas  metabolism  after  intake  of  food  should  be 
assigned  to  this  account.  But  a  number  of  authors,  as 
C.  Voit,  Rubner,  Magnus-Levy,  Jaquet  and  others  are  op- 
posed to  special  emphasis  of  this  factor.  Important  doubts 
have  been  raised  as  to  whether  the  special  rise  in  metabolism 
after  protein  feeding,  which  Rubner  has  spoken  of  as  the 
specific  dynamic  effect  of  the  protein,  is  to  be  explained 
entirely  by  the  digestion  work.32 

Specific-dynamic  Effect  of  Proteins. — It  is  to  be  under- 
stood that  the  idea  of  a  specific-dynamic  action  of  proteins 
is  not  in  the  least  antagonistic  to  the  "law  of  is o dynamics/' 
In  accordance  with  the  latter  the  different  food  materials 
may  in  the  matter  of  heat  production  be  mutually  inter- 
changed according  to  the  full  value  of  their  physiological 
availabilities  and  take  part  in  the  production  of  heat  with 
their  full  energy  values;  but  according  to  Rubner 's  idea 
particularly  in  case  of  the  proteins  a  greater  part  of  the 
energy  is  lost  by  change  into  heat  for  the  activities  of  the 
cellular  life  as  such. 

As  heat  production  within  the  body  of  the  warm-blooded 
animal  has  to  do  with  compensating  for  the  loss  of  heat  in 
the  body  surface,  Rubner  is  of  the  opinion  that  the  specific- 
dynamic  influence  of  foods  can  be  seen  in  the  clearest  pos- 
sible relation  by  excluding  the  surface  heat  loss  by  providing 
a  temperature  equal  to  that  of  the  body  in  the  surrounding 
medium.  He  therefore  kept  a  dog  at  33°  C,  first  determined 
the  minimal  metabolism  in  fasting,  and  then  gave  for  a  time 
a  diet  made  up  of  proteins,  or  of  fats,  or  carbohydrates,  with 
the  same  caloric  equivalent  as  the  fasting  requirement,  and 
observed  the  production  of  heat.  Increase  of  heat  produc- 
tion was  observed,  for  sugar,  5.8  per  cent. ;  for  fat,  12.7  per 
cent.,  but  for  proteins,  30.9  per  cent.  A  protein  diet  with 
the  same  caloric  value  as  the  hunger-requirement  is  in- 

82  Cf.  Literature  concerning  the  specific  dynamic  action  and  the  work  of 
digestion;    L.  B.  Mendel,  Ergebn.  d.  Physiol..  11,  457-460,  1911. 


SPECIFIC-DYNAMIC  EFFECT  OF  PROTEINS         531 

capable  accordingly  of  maintaining  the  organism  in  equilib- 
rium ;  and  taking  the  fasting  energy  requirement  as  100,  an 
amount  of  energy  equivalent  to  about  140  in  the  form  of 
protein  is  required  to  reestablish  the  caloric  equilibrium. 
Graham  Lusk 33  expresses  this  in  the  following  schema : 

Fasting  requirement  in  potential  energy  =  100  calories. 
One  hundred  and  forty  calories  are  given  in  the  form  of 
meat  protein : 


40  calories  100  calories 

=  the   amount   of  heat   set     =  the    potential    energy, 
free  in  the  catabolism  of  available  for  cellular  life, 

the  protein,  available  in- 
stead of  heat  to  be  ob- 
tained by  chemical  regula- 
tion. 

With  reference  to  Eubner's  much  debated  idea  that 
protein  in  metabolism  is  split  into  a  nitrogenous  and  a 
nitrogen-free  moiety,  and  that  the  energy  obtained  from 
the  first  by  oxidation  is  not  available  for  the  vital  cellular 
activities  to  the  same  degree  as  the  energy  present  in  the 
other  part,  the  author  prefers  to  refrain  from  any  detailed 
comment,  as  the  idea  seems  to  him  altogether  hypothetical.34 
But  it  may  be  mentioned  that  recent  very  exact  calorimetric 
and  gasometric  experiments  by  Williams,  Eiche  and  Graham 
Lusk35  seem  to  favor  the  idea,  as  after  free  meat  feeding 
a  formation  de  novo  of  sugar  from  protein  seemed  to  take 
place  (v.  sup.,  p.  234  et  seq.).  Unquestionably  the  caloric 
effect  of  meat  feeding  is  sure  to  be  influenced  in  a  very 
important  degree  by  such  a  process. 

It  might  be  supposed  that,  in  reference  to  the  question 
upon  precisely  what  the  specific-dynamic  effect  of  protein 

53  Graham  Lusk :  Ernährung  und  Stoffwechsel,  2d  ed.,  translated  into  Ger- 
man by  Leo  Hess,  pp.  141-148,  1910. 

34  Cf.  A.  Magnus-Levy,  Handb.  d.  Pathol,  d.  Stoffw.,  2d  ed.,  1,  226,  231,  1906. 

35  H.  B.  Williams,  J.  A.  Riche  and  G.  Lusk  (Cornell  Med.  College),  Jour, 
of  Biol.  Chem.,  12,  349,  1912. 


532  ENERGY  EXCHANGE  AFTER  FOOD 

depends  and  to  what  degree  the  work  of  digestion  is  to  be 
held  for  the  related  phenomena,  possibly  experiments  with 
parenterally  introduced  protein  or  "mock  feeding"  would 
be  suitable  methods  of  definitely  differentiating  the  points 
in  question;  however,  according  to  the  judgment  of  as 
experienced  an  expert  in  this  subject  as  W.  Caspari 36  this 
does  not  seem  to  be  the  case.  A  number  of  authors  are  dis- 
posed to  the  view  that  introduction  of  protein  acts  in  a 
sense  as  a  direct  stimulant  which  excites  the  cells  of  the  body 
to  increased  oxidation  processes.  Possibly  the  recent  ob- 
servations of  E.  Gräfe,  suggesting  that  over-nutrition  in 
animals  and  human  beings  induces  a  decided  exaggeration 
of  the  combustion  processes,  may  be  interpreted  in  this 
sense ;  a  man,  in  whom  in  the  course  of  six  weeks  an  increase 
of  weight  of  fifty  per  cent,  was  attained  by  excessive  hyper- 
nutrition,  manifested  a  very  marked  exaggeration  of  heat 
production  not  only  after  introduction  of  food  but  also  in 
periods  of  fasting  (in  this  last  condition  an  increase  of 
eighty  per  cent.)  .37  Zuntz  and  Hagemann  have  found  that  the 
increased  consumption  of  oxygen  in  the  horse  after  feeding 
maize  amounts  to  about  twenty-five  per  cent,  more  than  when 
the  same  amount  of  oats  is  fed,  and  they  remark  that  it  would 
be  quite  a  risk  to  assume  in  this  connection  any  work-in- 
crease on  the  part  of  the  digestive  tract  capable  of  raising 
the  metabolic  process  by  as  much  as  one-fourth.  They  be- 
lieve the  most  likely  idea  is  that  there  is  some  unknown 
chemical  substance  in  the  corn  which  stimulates  the  cells 
of  the  animal  body  to  exaggerated  oxidations.  Jaquet38 
comes  to  the  conclusion  from  this  that  if  such  possibility  be 

~s  Literature  in  reference  to  the  Specific-dynamic  Effect  of  Protein :  A. 
Jaquet,  Ergebn.  d.  Physiol.,  2',  478-486,  1902 ;  A.  Löwy,  Handb.  d.  Biochem.,  4', 
266-271,  277-284,  1908;  R.  Tigerstedt,  Nagel's  Handb.  d.  Physiol.,  1,  351-375, 
1901;   Handb.  d.  Biochem.,  4",  1-42,  1910;    W.  Caspari,  ibid.,  4',  775-778,  1911. 

37  E.  Gräfe  and  D.  Graham  (Med.  Clinic,  Heidelberg),  Zeitschr.  f.  physiol. 
Chem.,  73,  1,  1911;  E.  Gräfe  and  R.  Koch  (Med.  Clinic,  Heidelberg),  Deutsch. 
Arch.  f.  klin.  Med.,  106,  564,  1912. 

38  A.  Jaquet,  1.  c,  p.  486. 


SPECIFIC-DYNAMIC  EFFECT  OF  PROTEINS        533 

accepted  in  case  of  maize,  there  is  no  reason  why  it  should 
be  debated  for  the  proteins  in  general. 

Contrary  to  the  attempt  to  refer  the  specific-dynamic 
effect  of  protein  to  a  heightened  renal  activity,  Tangl  has 
proved  that  it  is  manifested  as  well  after  the  kidneys  have 
been  extirpated.39 

Gigon  takes  the  middle  ground  between  the  Zuntz  and 
the  Eubner  hypotheses,  accepting  the  digestive  work  as 
playing  an  important  part.  Although  the  economy  in  its 
minimal  metabolism  is  independent  of  the  immediate 
introduction  of  food,  there  is  to  be  observed  after  protein 
introduction  an  increase  of  protein  combustion  in  which,  too, 
processes  of  intermediate  conversion  of  protein  into  carbo- 
hydrate and  of  the  latter  into  fat  are  involved.40 

39  Tangl   (Budapesth),  Biochem.  Zeitschr.,  84,  1,  1911. 

40  A.  Gigon  (Basel),  Pflüger's  Arch.,  UO,  509,  1911. 


CHAPTER  XXII 
OXIDATION  FERMENTS 

Theory  of  Action  of  Oxidases. — The  fact  that  the  nutri- 
ent substances,  not  affected  by  molecular  oxygen  at  low 
temperature,  are  oxidized  with  the  greatest  ease  within  the 
economy  into  their  end-products  is  a  really  wonderful  phe- 
nomenon. One  can  at  once  realize  how  remarkable  this  is 
by  reflecting  upon  the  intense  heat  requisite  to  completely 
burn  up  a  bit  of  protein  upon  platinum  foil,  although  it  is 
mere  play  for  the  body  to  break  down  large  quantities  of 
protein,  and  that,  too,  almost  completely.  The  problem  of 
just  how  this  can  be  accomplished  has  occupied  students 
of  nature  ever  since  they  began  to  delve  into  the  enigma  of 
life  from  the  chemical  point  of  view.  The  thought  must 
necessarily  at  once  obtrude  itself  that  the  oxygen  must 
exist  in  an  extremely  effective,  "active"  form;  and  in  har- 
mony with  the  advances  in  chemical  science  efforts  have  been 
faithfully  made  to  give  concrete  form  to  this  idea. 

The  idea  of  an  ozonization  of  the  intracorporeal  oxygen, 
emanating  from  the  original  brain  of  Schönbein,  although  it 
deeply  impressed  his  contemporaries,  has  not  been  able  to 
withstand  criticism.  The  supposition  upheld  by  Hoppe- 
Seyler  of  an  activation  of  the  molecular  oxygen  by  rupture 
of  the  oxygen  molecule  after  the  manner  of  a  reduction  pro- 
cess proved  more  fruitful.  The  observation,  for  example, 
that  in  the  presence  of  oxygen  palladium  foil  charged  with 
hydrogen  is  capable  of  oxidizing  indigo  may  as  a  process  be 
outlined  in  somewhat  the  following  manner : 

Pd2H        HO.H 

-1-  +  02  =  2Pd2  +  2H20  +  H202, 

Pd2H        HO.H 

peroxide  of  hydrogen  being  thus  generated  with  its  effective 
oxidizing  capacity. 

Traube  seems  to  have  been  the  first  to  adopt  the  idea  of 

534 


THEORY  OF  ACTION  OF  OXIDASES  535 

an  "oxidizing-ferment"  and  to  give  expression  to  the  happy 
thought  that  there  occur  in  the  body  readily  oxidizable  sub- 
stances ("autoxidizable")  which  have  the  power  of  trans- 
ferring the  oxygen  in  active  form  to  substances  which  are 
oxidizable  with  difficulty  ( ' '  dys  oxidizable' ') ,  such  as  the  nutri- 
ent materials.  On  this  as  a  foundation  Engler  and  Bach  later 
built  up,  with  their  associates,  their  peroxide  theory.  In 
this  theory  it  is  supposed  that  the  oxygen  attaches  itself  to 

the  autoxidizable  substances  in  the  form      i     and  produces 

— o 

addition-products  of  the  type  R<J     (moloxide)  or  of  the 

R— O     .  .     . 

type        |  .  As  a  special  instance  of  such  peroxide  formation 
R — O 

the  production  of  hydrogen  peroxide  may  serve,  zinc  in  the 
presence  of  water  and  oxygen  being  regarded  as  exerting 

...  .  OH.H 

an  oxidizing  action :  Zn  +  +  02  =  Zn  (OH),  +  H2o2.  Accord- 

OH.H 

ing  to  Engler  and  Herzog  oxidations  of  this  type  may  be 
represented  by  the  following  schema :  A  -f  02  =  A02,  or 
again  in  the  sense  of  an  equivalence,  A  -j-  02^z^A02  (as,  for 
example,  haemoglobin,  oxygen  and  oxyhemoglobin).  A 
second,  not  an  autoxidizable  substance,  B  (" acceptor") 
can  be  oxidized  by  A02  in  the  sense :  A02  +  B  =  AO  -f-  BO. 
By  analogous  process  we  may,  for  example,  explain  why 
indigo  is  not  attacked  by  molecular  oxygen,  although,  if  an 
indigo  solution  is  shaken  up  with  benzaldehyde,  both  sub- 
stances become  oxidized.  The  benzaldehyde  is  transformed, 
presumably  under  the  influence  of  the  atmospheric  oxygen, 

-  ,      ,  .  ,       /C6H5.COH  +  O,  =  C«H6.CO.O\ 

into  benzoyl-hydrogen  peroxide  (  j  j, 

V  H.O/ 

and  this  then  (with  formation  of  benzoic  acid,  C6H5.COOH) 

acts  as  an  oxidizing  agent  upon  the  indigo. 

But  to  return  to  the  above  schema,  AO  (the  oxide  of  the 

autoxydator)  is  capable  of  oxidizing  another  molecule  of  B, 


536  OXIDATION  FERMENTS 

the  acceptor  (AO  +  B  =  A  -j-  BO),  and  the  autoxydator,  A, 
is  thereby  regenerated;  and  the  final  effect  of  the  whole 
process  seems  given  by  the  equation,  2B  -j-  02  =  2BO.  A 
in  the  above  acts  as  a  catalysator  and  simply  conveys  two 
atoms  of  oxygen  to  two  atoms  of  B. 

These  points  generally  acquire  increased  physiological 
interest  from  certain  findings  by  Kastle  and  Loevenhart,  in- 
dicating that  inorganic  and  organic  peroxides  (as  lead-,  man- 
ganese- and  benzoyl-peroxide)  are  capable  of  producing  a 
blue  color  with  tincture  of  guaiac,  just  as  vegetable  tissues 
do.1 

With  these  introductory  remarks,  which  naturally  make 
no  pretense  in  any  way  to  completeness,  we  may  at  once 
proceed  to  consideration  of  the  oxidases. 

Only  the  principal  points  are  here  presented,  especially 
as  F.  Battelli  and  Miss  Lina  Stern  have  recently  collected 
the  general  literature  of  the  subject  (over  six  hundred  orig- 
inal papers)  in  an  excellent  and  easily  accessible 
monograph.2 

Peroxidases  and  Oxygenases. — In  the  confused  mass  of 
observations  which  relate  to  the  oxidation  ferments  a  certain 
degree  of  system  was  first  developed  by  the  extensive  studies 
of  Bach  and  Chodat.  Following  these  writers  we  use  the 
term  peroxidases  for  those  ferments  which  manifest  their 
influence  only  in  the  presence  of  peroxides  of  organic  or 
inorganic  character,  catalytically  accelerating  their  disin- 
tegration with  the  result  of  setting  free  active  oxygen.  Those 
peroxides  which  we  fancy  as  substances,  not  of  fermentative 
nature,  but  capable  of  taking  up  oxygen,  acting  only  weakly 

1  Literature  upon  the  Theory  of  Action  of  Oxidases:  J.  Loeb,  Vorlesungen 
über  die  Dynamik  der  Lebenserscheinungen,  pp.  30-35,  1906;  W.  Manchot, 
Verh.  d.  Phys.-Med.  Ges.,  Würzburg,  39,  1908,  S.  A.;  J.  H.  Kastle,  The  Oxidases, 
U.  S.  Hygienic  Lab.  Bull.,  50,  24-30,  1909;  C.  Oppenheimer,  Die  Fermente,  3d 
ed.,  338-341;  A.  Montuori,  Mem.  della  S'oc.  ital.  delle  Scienze,  ser.  3,  Tomo  XVI, 
Roma,  1910;  C.  Engler  and  R.  O.  Herzog  (Karlsruhe),  Zeitschr.  f.  physiol. 
Chem.,  59,  327,  1909;    F.  Battelli  and  L.  Stern,  cf.  next  reference:    pp.  251-259. 

2  F.  Battelli  and  L.  Stern  (Geneva),  Ergebn.  d.  Physiol.,  12,  96^268,  1912. 


ERRORS  IN  STUDY  OF  PEROXIDASES  537 

as  oxidizing  agents  in  themselves  but  acquiring  powerful 
oxidizing  influence  by  contact  with  the  peroxidases,  are 
called  oxygenases  by  Bach  and  Chodat — a  term  which  is 
obviously  not  particularly  fortunately  selected  as  it  suggests 
for  these  substances  the  idea  of  a  ferment  nature  which 
does  not  belong  to  them.  In  their  work  on  vegetable  ma- 
terial of  different  kinds  Bach  and  Chodat  succeeded  in 
separating  the  oxygenases  and  peroxidases  from  each  other 
by  fractional  precipitation  with  alcohol,  etc.  The  peroxi- 
dases, in  spite  of  their  presumed  enzymic  nature,  are  fairly 
resistant  substances,  which  can  be  kept  for  years  under 
proper  conditions ;  but  the  oxygenases  are  extremely  labile 
and,  in  accord  with  their  peroxide  character,  are  at  once 
broken  up  by  water  with  formation  of  hydrogen  peroxide. 
It  is  scarcely  any  wonder  that  while  the  peroxidases  are  met 
in  the  vegetable  kingdom  in  very  wide,  one  might  almost  say 
general  distribution,  oxygenases  are  to  be  recognized  only 
exceptionally.3 

No  further  discussion  will  be  given  to  the  vegetable  per- 
oxidases. What,  however,  of  the  distribution  of  animal 
peroxydases  ? 

Sources  of  Error  in  the  Study  of  Peroxidases. — In  under- 
taking, some  years  ago,  in  association  with  E.  v.  Czyhlarz,4 
to  answer  this  question,  the  author  recognized  at  the  out- 
start  that  the  confusion  prevailing  upon  the  subject  was  due 
to  failure  to  take  into  consideration  a  number  of  important 
items. 

In  the  first  place,  as  long  as  we  continue  to  look  upon  the 
peroxidases  as  ferments,  we  should  insist,  too,  upon  their 
basic  differentiation  from  the  peroxidase-like  action  of 
haemoglobin.     Guaiaconic  acid  and  similar  reagents  in  the 

3  Literature  upon  Animal  Peroxidases:  A.  Bach  and  Chodat,  Biochem.  Cen- 
tralbl.,  1,  417,  1903;  A.  Bach,  ibid.,  9,  1909;  Kastle,  1.  c,  110-119;  Vernon, 
1.  c,  pp.  216-217;  Oppenheimer,  1.  c,  342-349,  353-361,  386-390;  F.  Samuely, 
Handb.  d.  Biochem.,  1,  570-572,  1909;  E.  v.  Czyhlarz  and  O.  v.  Fürth,  Hof- 
meisters Beitr.,  10,  358,  1907;  F.  Battelli  and  L.  Stern,  1.  c,  217-238. 

*  Czyhlarz  and  Fürth,  1.  c. 


538  OXIDATION  FERMENTS 

presence  of  peroxide  of  hydrogen  are,  however,  just  as 
readily  changed  into  their  colored  derivatives  by  minute 
quantities  of  blood  as  by  a  vegetable  peroxidase  or  bit  of  liv- 
ing plant  tissue.  In  view  of  the  great  practical  difficulty  to 
thoroughly  free  vertebrate  tissue  of  residual  amounts  of 
blood  it  seems  by  no  means  an  easy  task  to  differentiate 
between  the  influence  of  blood  and  the  effect  of  peroxidases. 

Further  difficulties  are  met  in  the  fact  that  the  action  of 
peroxidases  is  closely  connected  with  the  presence  of  per- 
oxide of  hydrogen;  that  the  tissues,  however,  contain  at  the 
same  time  agents,  the  catalases,  to  be  considered  hereafter, 
which  disintegrate  hydrogen  peroxide  and  thus  antagonize 
the  peroxidases.  It  is  clear,  too,  that  easily  oxidizable  sub- 
stances of  various  kinds  may  cause  disturbance  by  abstract- 
ing the  activated  oxygen,  thus  diverting  it  from  the  reagents. 

Finally,  too,  much  of  the  confusion  attaching  to  the  ques- 
tion of  the  oxidases  comes  from  the  fact  that  under  certain 
circumstances  when  guaiac  resin  (which  since  the  time  of 
Schönbein  has  been  regarded  more  or  less  as  a  universal  re- 
agent for  oxidases)  is  added  to  tissue  extracts,  even  in  the 
absence  of  hydrogen  peroxide  the  characteristic  blue  reac- 
tion is  observed.  This  has  led  to  the  recognition  of ' '  direct ' ' 
and  "indirect"  oxidases.  According  to  Bach  and  Chodat 
the  former  are,  however,  nothing  more  than  mixtures  of 
oxygenases  (therefore  of  peroxides)  and  peroxidases.  It 
should  also  be  recalled  that  a  solution  of  guaiac  resin  is 
likely  to  undergo  spontaneous  change  if  exposed  to  the  air 
and  can  become  charged  with  oxygen  combined  as  in  per- 
oxides. This  difficulty  may  be  avoided  by  employing  the 
active  principle,  guaiaconic  acid,  instead  of  the  resin,  using 
the  acid  in  chemically  pure  state  and  in  freshly  prepared 
solution.  Guaiaconic  acid  is  properly  employed,  as  Carlson 
has  recommended,  in  combination  with  hydrogen  peroxide 
but  not  with  turpentine  resin,  as  in  the  well  known  blood  test 
proposed  by  the  Dutch  physician  Van  Deen  in  1861,  in  which 


DETECTION  OF  PEROXIDASES  539 

the  blue  color  was  used  as  a  blood  test  by  shaking  the  speci- 
men up  in  tincture  of  guaiac  and  old  oil  of  turpentine.  The 
action  of  the  turpentine  in  this  latter  depends  upon  the  inci- 
dental and  inconstant  presence  of  peroxides  in  it,  developing 
especially  in  the  formation  of  resin.5 

Iodine  Reaction. — In  the  detection  of  peroxidases  in  ani- 
mal tissues  the  frequently  employed  iodine  reaction  of  Bach 
and  Chodat  seemed  to  Czyhlarz  and  the  author  a  fairly  suited 
method  (separation  of  iodine  from  acidulated  iodide  of 
potassium  solution  in  the  presence  of  hydrogen  peroxide  and 
detection  of  the  liberated  iodine  by  means  of  starch  paste) , 
in  that  (in  differentiation  from  the  oxidation  of  guaiaconic 
acid  and  other  cyclic  chromogens)  the  oxidation  of  hydriodic 
acid  was  not  catalytically  accelerated  by  haemoglobin  in  the 
experiment  conditions  employed  by  the  writers.  They  were 
able  by  this  method  to  establish  the  presence  of  true  per- 
oxidases in  leucocytes  (pus  cells),  lymphoid  tissue  (bone 
marrow,  spleen,  lymph  nodes),  and  in  sperm.  They  em- 
phasize the  point,  however,  that  the  test  can  be  regarded  as 
conclusive  only  when  the  reaction  is  positive,  not  when  it 
is  negative,  because  of  the  impossibility  of  excluding  inhibi- 
tion of  the  reaction  by  albumins  and  other  iodine-fixing  tissue 
constitutents.  As  a  matter  of  fact,  J.  Wolff  and  E.  de  Stöklin 
have  been  able  to  show  that  oxyhemoglobin  (present,  of 
course,  in  all  tissues)  under  certain  changes  of  experimental 
conditions  will  also  behave  quite  like  a  vegetable  peroxidase 
toward  iodide  of  potassium  and  hydrogen  peroxide,  if  care 
is  taken  to  immediately  remove  any  excessive  iodine.6  Ac- 
cording to  F.  Battelli  and  Lina  Stern  this  is  also  true  if 
in  arranging  the  reaction  hydrogen  peroxide  is  replaced  by 
ethylhydrop  er  oxide ;  although  it  is  at  present  impossible 
to  say  what  is  the  cause  of  the  difference  of  behavior  of  the 
haemoglobin  to  the  two  peroxides.     The  authors  just  re- 

5  Cf.  B.  Moore  and  E.  Whitley,  Biochem.  Jour.,  k,  136,  1909. 

6  J.  Wolff  and  E.  de  Stöcklin  (Instit.  Pasteur,  Paris) ,  Ann.  Instit.  Pasteur, 
25,  319,  1911. 


540  OXIDATION  FERMENTS 

f erred  to  note  the  fact  that  frequently  the  iodine  reaction  is 
noticeably  weaker  with  blood  than  with  many  of  the  tissues, 
this  point  then  serving  to  suggest  the  presence  of  a  true  per- 
oxidase in  the  tissue  apart  from  the  blood  which  may  be  in 
them.7  The  use  of  ethylhydroperoxide  in  place  of  hydrogen 
peroxide  is  undoubtedly  a  step  in  advance,  as  it  is  not 
affected  by  tissue  catalases. 

Oxidation  of  Formic  Acid. — Another  method  for  the  de- 
tection of  peroxidases  in  tissues,  for  which  credit  is  due 
F.  Battelli  and  L.  Stern,  depends  on  the  ability  of  the  tissues 
of  higher  animals  to  oxidize  formic  acid  in  vitro  in  the  pres- 
ence of  hydrogen  peroxide  with  production  of  carbonic  acid 
(H.COO  H  +  0  =  C02  +  H20).  By  the  use  of  this  method, 
by  determining  the  C02,  it  has  been  shown  that  the  liver  more 
than  other  tissues  has  a  particularly  strong  power  of  oxidiz- 
ing formic  acid.8 

Purpurogallin  Method. — A  gravimetric  method  recom- 
mended for  estimating  peroxidases,  used  frequently  by  Bach 
and  Chodat,  depends  on  the  oxidation  separation  of  the  rela- 
tively insoluble  purpurogallin  from  a  solution  of  pyrogallol. 

Phenolphthalin  Method. — In  the  experiments  carried  on 
with  E.  v.  Czyhlarz  the  author  has  performed  many  estima- 
tions by  the  phenolphthalin  method  of  Kastle  and  Shed.9  It 
was  found  that  the  oxidation  transformation  of  the  colorless 
phenolphthalin  into  Phenolphthalein  with  its  brilliant  red 
color  in  alkaline  solution  is  well  adapted  to  spectrophotome- 
tric  measurement,  a  sharply  defined  absorption  band  occur- 
ring about  the  middle  of  the  spectrum.  However,  the  use- 
fulness of  the  method  is  decidedly  impaired  by  the  fact  that 
an  alkaline  solution  of  phenolphthalin  may  rapidly  undergo 
spontaneous  reddening  in  the  presence  of  hydrogen- 
peroxide. 

7F.  Battelli  and  L.  Stern  (Geneva),  Biochem.  Zeitschr.,  13,  49-59,  1908. 

8F.  Battelli  and  L.  Stern  (Geneva),  Biochem.  Zeitschr.,  13,  44,  1908; 
Z.  Sarafoff,  Dissert.  Univ.  of  Geneva,  1908,  cited  in  Jahresher.  f.  Tierchem.,  39, 
528,  1909. 

»Kastle  and  Shed,  Amer.  Chem.  Jour.,  26,  26,  1901. 


MEASUREMENT  OF  OXYGEN  CONSUMPTION       541 

Leukomalachite-green  Method. — The  author  believes  a 
real  advance  has  been  made  in  the  discovery  in  leukomal- 
achite-green  of  a  reagent  which  possesses  the  advantages 
but  not  the  disadvantages  of  phenolphthalin.  The  leuko- 
base  of  malachite-green,  in  its  chemical  construction  a  tri- 

phenylme thane  derivative,  CH(-c6H4  •  N(CH3)2,  is  recommended 

XIÄ  •  N(CH3)? 

by  B.  and  0.  Adler  10  as  an  extremely  reliable  reagent,  the 
colorless  solution  of  the  substance  being  changed  into  mal- 
achite-green at  once  in  the  presence  of  hydrogen  peroxide 
by  very  small  amounts  of  blood.  It  was  found  by  the 
author  and  his  associate  that  a  solution  of  the  leukobase  in 
acetic  acid  with  hydrogen  peroxide  added  serves  also  as  an 
excellent  reagent  for  the  detection  of  peroxidases.  The 
solution  remains  unchanged  for  a  relatively  long  time ;  but 
on  the  addition  of  a  small  amount  of  a  solution  of  a  per- 
oxidase at  once  an  emerald  green  color  appears,  deepening 
more  or  less  rapidly.  As  a  properly  diluted  solution  of 
malachite-green  shows  a  sharply  defined  absorption  band  in 
the  middle  of  the  spectrum,  it  is  quite  possible  to  determine 
quantitatively  by  spectrophotometry  the  amount  of  mal- 
achite-green which  has  been  produced  by  the  enzymic  influ- 
ence from  the  leukobase  with  considerable  accuracy.  As 
the  observation  requires  but  a  few  moments,  and  can  be 
repeated  as  often  as  may  be  desired  and  at  whatever  inter- 
vals may  seem  best  in  the  same  test,  one  is  in  position,  even 
if  only  a  few  cubic  centimeters  of  material  be  available,  to 
follow  the  process  of  oxidation  step  by  step  and  record  it 
graphically  by  a  curve  (with  the  time  as  abscissa  and  the 
amount  of  newly  formed  malachite-green  as  ordinate). 

Measurement  of  Oxygen  Consumption. — C.  Foa  pro- 
ceeds upon  a  difficult  principle,  registering  by  means  of  a 
Mosso  phethysmograph  the  amount  of  oxygen  consumed  in 
the  oxidation  of  aromatic  substances  (pyrogallol,  hydro- 
chinon,  etc.)  by  peroxidases   (the  method  being  based  on 

10  R.  and  O.  Adler,  Zeitschr.  f.  physiol.  Chem.,  )tl,  58,  1904. 


542  OXIDATION  FERMENTS 

the  lowering  of  pressure  within  an  enclosed  system).11  This 
method  has  been  improved  by  H.  II.  Bunzel  in  Washington ; 
in  the  latter 's  method  the  containers  are  fastened  to  a  shak- 
ing apparatus  placed  in  a  thermostat  and  the  changes  in 
pressure  occasioned  by  the  consumption  of  oxygen  are  read 
off  on  manometer  tubes.12 

Limits  of  Availability  of  Above  Methods. — The  adverse 
criticism  which  Foa  expresses  for  all  the  existing  methods 
except  his  own  is  certainly  not  correct  in  case  of  the  mal- 
achite-green method;  and  in  the  author's  opinion  it  is  ex- 
tremely doubtful  whether  his  method  is  practically  any  ad- 
vance over  the  latter.  The  total  oxidizing  effect  performed 
by  an  extract  or  a  tissue-pulp  can  be  determined  with  ap- 
proximate correctness  by  the  methods  mentioned  and  by 
several  other  procedures  13  and  compared.  However,  the 
principal  difficulty  in  the  study  of  tissue  peroxidases  is  not  to 
be  found  here.  There  are  two  great  impediments  in  the 
way,  over  which  research  has  hitherto  been  stumbling.  The 
one  is  the  impossibility  to  quantitatively  extract  the  tissue 
peroxidases  (the  same  is  true  of  other  "endoenzymes") 
from  the  tissues;  the  other  is  the  blood  in  the  tissues, 
which,  because  blood  may  also  act  like  a  peroxidase  and 
because  it  can  hardly  be  fully  removed,  makes  all  compara- 
tive study  of  the  peroxidase-content  of  tissues  a  matter  of 
uncertainty.  That  there  are  differences  in  this  respect  be- 
tween the  various  tissues  is  shown  by  histochemical  observa- 
tion. If,  for  example,  a  cover-glass  preparation  of  gonor- 
rhoeal  pus  be  treated  with  a  peroxidase  reagent,  as  benzidin- 
monosulphite  of  soda,  the  leucocytic  granules  alone  will 
become  colored  at  a  certain  stage  of  hydrogen  peroxide  con- 
centration ;  the  myelocytes  from  the  bone-marrow  also  are 
easily  stained,  while  the  lymphocytes  react  only  at  a  higher 

11  C.  Foä  (Mosso's  Lab.,  Turin),  Biochem.  Zeitschr.,  11,  382,  1908. 

12  H.  H.  Bunzel,  U.  S.  Dept.  Agricult.,  Bureau  of  Plant  Industry,  Bull.  No. 
238,  Washington,  1912. 

13  Cf.  Literature:    H.  H.  Bunzel,  1.  c. 


PEROXIDASE-LIKE  ACTION  OF  HAEMOGLOBIN      543 

concentration  and  the  erythrocytes  at  still  higher  degree  of 
concentration  of  hydrogen  peroxide.14  Another  and  per- 
haps seemingly  impertinent  question,  however,  is  whether 
it  is  actually  worth  the  trouble  to  devote  so  interminably 
great  an  amount  of  work  to  these  matters.  The  author's 
personal  views  on  the  subject  may  be  deferred  until  after 
the  presentation  of  the  problems  of  the  peroxidase-nature 
of  haemoglobin  and  of  the  artificial  peroxidases. 

Peroxidase-iike  Action  of  Hämoglobin. — The  question 
may  be  at  once  considered  whether  there  is  a  special  funda- 
mental difference  between  the  oxygen  carrying  action  of 
haemoglobin  and  that  of  the  true  peroxidases. 

As  this  peroxidase-like  action  of  haemoglobin  is  also 
characteristic  of  its  color  constituent,  haematin,  but  as  the 
latter  is  in  the  fullest  sense  a  thermostable  substance,  it 
might  well  be  believed  that  there  can  be  no  suggestion  of  iden- 
tity, because  the  peroxidases  in  accordance  with  theirf  erment 
character  must  necessarily  be  thermolabile  substances.  For- 
merly this  was  the  common  opinion ;  and  it  is  true  that  gener- 
ally when  a  tissue  containing  peroxidases  is  boiled  its  effici- 
ency in  this  direction  is  seen  to  disappear.  This,  however, 
cannot  be  regarded  as  establishing  a  fundamental  difference, 
as  von  Czyhlarz  and  the  author,15  and  other  observers  as 
well,  have  occasionally  dealt  with  peroxidase  solutions  which 
retained  their  activity  almost  at  the  boiling  temperature. 
Battelli  and  Stern  in  their  peroxidase  experiments  with 
formic  acid  have  noted  an  increase  of  activity  with  increase 
of  temperature  up  to  38-^0°  C.  But  from  this  point  further 
increase  of  temperature  caused  a  lowering  of  oxidation, 
which  stopped  almost  completely  at  65°  C. ;  while  the  oxida- 
tion of  formic  acid  by  haemoglobin  in  the  presence  of  hydro- 
gen peroxide  is  distinctly  more  active  at  a  temperature  of  55- 

14  R.  Fischel,  Wiener  klin.  Wochenschr.,  23,  1557,  1910;  cf.  also  F.  Winkler, 
Folia  Haematol.,  4,  323,  1907;    5,  17,  1908. 

15  E.  v.  Czyhlarz  and  O.  v.  Fürth,  1.  c,  p.  367;  cf.  A.  van  der  Haar 
(Utrecht),  Ber.  d.  deutsch,  ehem.  Ges.,  43,  1321,  1910. 


544  OXIDATION  FERMENTS 

60°  C.  than  at  38°  C.16  The  tyrosinases,  a  special  variety  of 
peroxidases,  dealt  with  at  length  in  connection  with  the 
formation  of  melanin  (Vol.  I  of  this  series,  pp.  527-536, 
Chemistry  of  the  Tissues),  are  thermolabile  in  a  high  degree. 

Another  rather  characteristic  point  of  difference  between 
the  oxygen  convection  by  haemoglobin  and  by  the  peroxidases 
was  pointed  out  by  the  author's  associate  and  himself.  In 
graphic  registration  of  the  results  obtained  by  the  spectro- 
photometric  malachite-green  method,  using  the  time  values 
as  abscissas  and  the  appropriate  amounts  of  oxidation  prod- 
uct as  ordinates,  it  became  evident  that  the  catalyzing  re- 
actions of  haßmatin  were  represented  by  almost  straight  lines 
which  proceeded  from  the  coordinate  starting  point  at  dif- 
ferent angles.  The  reaction  of  true  animal  peroxidases 
(obtained  from  pus  cells),  however,  correspond  to  curves 
which  after  a  constant,  more  or  less  sharp  rise  suddenly 
turn  toward  the  horizontal  and  continue  parallel  to  the 
abscissa  axis.  This  corresponds  closely  with  the  curves 
which  Bach  and  Ghodat  repeatedly  observed  in  case  of  vege- 
table peroxidases.  Bach,17  therefore  (as  well  as  Lesser 18 
and  Buckmaster),19  is  of  the  opinion  that  hsematin  behaves 
somewhat  like  a  chemically  definite  catalysator,  while  the 
action  of  true  animal  peroxidases  approaches  that  of  other 
ferments. 

We,  therefore,  have  reason  for  the  time  being  to  regard 
the  blood  coloring  matter  as  a  "  pseudoperoxidase"  in  con- 
tradistinction to  the  true  oxidases. 

On  the  other  hand  again,  W.  Madelung  is  of  the  opinion 
that  the  activation  of  peroxides  by  the  ha&moglobin  is  func- 
tionally not  different  from  their  activation  by  the  tissue 
peroxidases,  inasmuch  as  apparently  there  also  exist  in  the 

16  F.  Battelli  and  L.  Stern,  1.  c,  p.  88. 

17  A.  Bach  (Geneva),  Biochem.  Centralbl.,  9,  1909  Sep.,  p.  20. 

18  E.  J.  Lesser,  Zeitschr.  f.  Biol.,  49,  571,  1907. 

18  A.  Buckmaster,  Jour,  of  Physiol.,  85,  Proc.  XXXV,  1907;  37,  Proc.  XI, 
1908. 


DETECTION  OF  BLOOD  545 

tissues  complex  iron  compounds  which  may  be  capable  of 
conveying  oxygen;  the  haemoglobin  is  to  be  regarded  as  a 
compound  of  bivalent  iron  with  an  additional  valence  open 
for  a  loose  attachment 20  (vide  infra,  Chapter  XXIV). 

The  blue  respiratory  coloring  matter  of  the  Crustacea 
and  mollusks,  hcemocyanin  (Vol.  I  of  this  series,  p.  224, 
Chemistry  of  the  Tissues)  also  manifests  peroxidase  reac- 
tions in  a  striking  way,  here  apparently  related  with  the 
copper  it  contains.21 

Chemico-Legal  Detection  of  Blood  by  Means  of  Per- 
oxidase Reactions. — Brief  attention  may  be  given  to  a 
practical  phase  of  the  peroxidase  problem,  the  application 
of  the  peroxidase  reactions  of  haemoglobin  to  the  chemical 
detection  of  blood  for  legal  purposes.  For  this  purpose,  in 
addition  to  those  methods  which  are  based  on  a  specific  char- 
acteristic of  blood  coloring  matter  (as  spectroscopic  detec- 
tion, or  the  demonstration  of  Teichmann 's  crystals),  con- 
siderable use  has  been  made  of  the  peroxidase  reactions,  that 
is,  of  the  colors  which  solutions  of  guaiac  resin  or  guaiaconic 
acid,  aloin,  phenolphthalin,  leukomalachite-green,  benzidin, 
etc.,  assume  in  contact  with  hydrogen  peroxide  and  blood. 
The  marked  sensitiveness  of  these  reactions  has  led  to  their 
frequent  use  in  the  examination  of  drops  of  blood  on  cloth- 
ing, walls  and  utensils ;  but  the  value  of  evidence  thus  ob- 
tained has  been  restricted  before  courts  particularly  because 
of  the  fact  that  there  are  a  great  many  other  substances 
which  possess  the  power  of  conveying  oxygen  just  as  haemo- 
globin does,  as  for  example  rust,  a  number  of  iron-  and  cop- 
per-compounds, oxide  of  lead,  manganese  oxide,  chlorine, 
bromine,  iodine,  and,  too,  organic  substances  of  all  sorts  as 
pus,  saliva,  milk,  sweat  and  many  vegetable  materials.22 

20  W.  Madelung  (Heidelberg),  Zeitschr.  f.  physiol.  Chem.,  11,  204,  1911. 

21  C.  L.  Alsberg,  Arch,  f .  exper.  Pathol :  Sclimiedeberg's  Festschr.,  p.  40, 
1908;    C.  Fleig,  C.  R.  Soc.  de  Biol.,  69,  66,  110,  1910. 

22 Literature  of  Legal  Examination  of  Blood:  O.  Leers,  Die  forensische 
Blutuntersuchung,  Berlin,  J.  Springer,  1910;  cf.  also  O.  Schumm  and  E. 
Westphal  ( Hamburg-Eppendorf ),  Zeitschr.  f.  physiol.  Chem.,  Jf6,  510,  1905. 

35 


546  OXIDATION  FERMENTS 

The  author  has  endeavored  to  perfect  a  method  which 
shall  make  use  of  the  great  sensitiveness  of  the  peroxidase 
reactions  but  be  free  of  those  sources  of  error  which  are 
inherent  to  the  older  form  of  these  tests  and  which  have 
brought  their  forensic  value  into  question.  This  object  has 
been  attained  by  combining  a  test  described  by  Leers  23  with 
Adler 's  leukomalachite-green  test.  Leers  prepares  a 
haematin  extract  by  treating  the  object  supposed  to  be  con- 
taminated with  blood  with  a  concentrated  alcoholic  solution 
of  caustic  potash.  The  haematin  is  dissolved  out  by  shaking 
the  solution  well  with  pyridin,  is  then  reduced  by  a  reducing 
agent  to  hasmochromogen  and  examined  spectroscopically 
for  final  detection.  The  author  at  first  proceeds  in  the  same 
way  as  Leers ;  but  then  the  pyridin  solution  charged  with 
the  blood  coloring  matter  in  a  small  separating  funnel  is 
transferred  to  a  filter  paper  spread  out  on  a  glass  plate  and 
a  hydrogen  peroxide  solution  of  leukomalachite  base  in  dilute 
acetic  acid  is  added.  The  presence  of  haematin  is  shown  by 
an  intense  green  color.24  In  this  procedure  the  sources  of 
error  occasioned  by  the  true  peroxidases  (as  of  pus,  nasal 
mucus,  milk  and  vegetable  tissue)  are  excluded  by  previous 
boiling  with  concentrated  caustic  potash.  Moreover,  the 
disturbing  features  caused  by  inorganic  catalysators  need 
not  be  taken  into  consideration  as,  even  though  they  are  not 
thrown  out  (as  is  iron)  by  the  potash  in  the  form  of  inac- 
tive hydroxides,  they  will  not  dissolve  in  the  pyridin  solu- 
tion. Material  for  testing,  consisting  of  a  few  strands  of  a 
blood-soaked  fabric,  or  blood  stains  on  wood  or  iron  imple- 
ments may  be  successfully  and  with  certainty  identified,  even 
if  they  had  been  previously  boiled  in  water.  The  author  be- 
lieves that  this  method,  which  can  be  carried  through  in  a 
very  short  while  without  special  apparatus,  may  be  relied 
upon  to  fairly  answer  the  requirements  of  practice. 

23  Leers,  1.  c,  pp.  64-65,  and  Table  ii,  Fig.  2. 

24  For  details  of  the  process  consult  O.  v.  Fürth,  Zeitschr.  f .  angew.  Chem., 
24,  1625,  1911. 


ARTIFICIAL  PEROXIDASES  547 

Respiratory  Coloring  Substances. — When  it  is  recalled 
that  the  color  component  of  haemoglobin,  hsematin,  loses  its 
peroxidase-like  power  when  deprived  of  its  iron  by  conver- 
sion into  hsematoporphyrin,  and  when  recalled  also  that 
Gabriel  Bertrand,  who  has  devoted  himself  largely  to  the 
study  of  the  oxidases,  has  shown  that  the  effectiveness  of 
many  of  these  substances  is  related  to  the  manganese  they 
contain,25  the  suggestion  at  once  arises  that  the  real  point  of 
the  whole  oxidase  problem  may  perhaps  be  found  in  the 
catalytic  action  of  metals,  especially  those  which  because  of 
their  power  to  exist  in  different  stages  of  oxidation  are 
likely  to  serve  as  oxygen  carriers.  It  is  surely  not  an  acci- 
dental matter  that  not  only  haemoglobin,  but  also  many  other 
respiratory  pigments  which  are  found  in  the  invertebrates, 
as  the  echinochrome  of  the  seaurchins,  hcemerythrin,  and  the 
green  chlorocruorin  of  marine  worms  (cf.  Vol.  I  of  this 
series,  pp.  224,  225,  Chemistry  of  the  Tissues),  contain  iron; 
and  in  case  of  the  blue  hcemocyanin  in  the  blood  of  mollusks 
and  crustacese,  which  apparently  contains  copper,  it  should 
be  recalled  that  salts  of  copper  possess  in  a  high  degree  the 
ability  of  catalytically  conveying  oxygen.26  When,  too, 
it  is  remembered  that  we  know  that  colloidal  metals  27  or 
metals  in  combination  with  colloids  are  particularly  active 
in  this  respect,  there  is  every  reason  to  justify  the  attempt 
to  produce  artificial  oxidases. 

Artificial  Peroxidases. — Quite  a  number  of  experiments 
have  actually  been  presented  with  this  end  in  view.28  Thus 
Trillat29  found  that  in  bringing  together  a  salt  of  man- 
ganese, an  alkaline  hydroxide  and  a  colloid,  an  association 
resulted  which  is  entirely  comparable  to  natural  peroxidases. 

25  G.  Bertrand,  and  F.  Medigreceanu,  Compt.  Rendu.,  154,  1450,  1912. 
28  Cf.  H.  A.  Colwell,  Jour,  of  Physiol.,  39,  358,  1909. 

27  Cf.  C.  Foä  and  A.  Aggazzotti,  Biochem.  Zeitschr.,  19,  1,  1909. 

28  Literature  upon  Artificial  Peroxidases:  J.  H.  Kastle,  1.  c,  pp.  122-131; 
C.  Oppenheimer,  Die  Fermente,  3d  ed.,  348-351,  1909;  F.  Battelli  and  L.  Stern, 
Ergebn.  d.  Physiol.,  12,  241-243,  1912. 

28  A.  Trillat,  Compt.  rend.,  138,  274,  1904,  and  earlier  contributions. 


548  OXIDATION  FERMENTS 

Dony-Henault 30  obtained  peroxidase-like  products  by  mix- 
ing bloodserum  or  a  mucilage  with  weak  alkaline  reaction 
with  a  salt  of  manganese  and  precipitating  with  alcohol, 
adding  Rochelle  salt  as  a  suitable  material  to  prevent  the 
separation  of  manganese  oxide.  Euler  and  Bolin31  found 
a  typical  peroxidase  prepared  from  alfalfa  to  be  thermosta- 
ble and  certainly  not  an  enzyme,  but  rather  a  mixture  of 
neutral  salts  (especially  potassium  salts)  of  various  vege- 
table acids  (as  citric  acid,  malic  acid  and  mesoxalic  acid), 
and  that  such  salts  are  capable  in  plant  structures  and  juices 
containing  manganese  of  catalytically  accelerating  the  oxida- 
tion of  polyphenols,  etc.  According  to  J.  Wolff 32  if  yellow 
ferrocyanide  of  potassium  be  mixed  in  certain  porportions 
with  ferrous  sulphate,  blue  colloidal  ferrous  ferrocyanide 
will  be  obtained.  This  substance  behaves  quite  like  a  per- 
oxidase and  is  thermolabile.  The  oxidases  seemed  to  be 
peculiar  in  the  specificity  of  their  action  (as,  for  example,  a 
tyrosinase  may  fail  to  act  upon  hydrochinon).  However,  it 
has  been  found  that  artificial  colloids  may  also  manifest 
similar  specificity.  Thus  iron  in  the  presence  of  dibasic 
phosphate  produces  an  oxidation  of  hydrochinon,  but  re- 
mains inactive  if  the  phosphate  is  replaced  by  tribasic 
citrate. 

Doubt  as  to  the  Ferment  Character  of  Peroxidases. — 
These  and  similar  observations  necessarily  arouse  serious 
doubts  as  to  the  enzymic  nature  of  peroxidases.  Bertrand 33 
regards  the  sensitiveness  of  a  number  of  peroxidases,  par- 
ticularly the  "laccases,"  toward  acids  as  supporting  his 
view  of  the  role  played  by  metals  in  oxidase-activity.    If, 

30 O.  Dony-Henault  (Instit.  Solvay,  Brussels),  Bull.  Acad.  roy.  de  Belgique, 
1907,  1908,  1909. 

31 H.  Euler  and  J.  Bolin  (Stockholm),  Zeitschr.  f.  physiol.  Chem.,  57,  80, 
1908;     61,  72,  1909. 

32  J.  Wolff,  numerous  papers  in  Compt.  rend,  and  in  C.  R.  Soc.  de  Biol.,  1908, 
1909;  partly  in  association  with  E.  de  Stöcklin;  also  Thesis,  Paris,  1910,  and 
Ann.  Instit.  Pasteur,  23,  841,  1909;    2k,  789,  1910. 

33  G.  Bertrand,  Ann.  Instit.  Pasteur,  21,  673,  1907. 


ARE  PEROXIDASES  FERMENTS?  549 

for  example,  it  be  assumed  that  the  laccase  is  a  manganese 
compound  which  readily  undergoes  hydrolytic  dissociation 
following  the  formula,  R  Mn  +  H20  =  RH2  +  MnO,  it  may 
be  at  once  appreciated  why  even  a  small  amount  of  acid 
would  arrest  the  action.  In  case  of  other  peroxidases  iron 
may  play  the  same  role.  On  the  other  hand,  it  must  be  proved 
that  there  really  are  peroxidases  which  are  active  in  an  acid 
medium  and  which  are  found  to  be  free  of  manganese  and 
of  iron.34 

Efforts  have  also  been  made  to  solve  the  question  of 
the  enzymic  nature  of  peroxidases  by  study  of  their  fer- 
ment kinetics.  Bach  and  Chodat  have  noted  in  oxidation  of 
pyrogallol  by  vegetable  peroxidases  that  the  amount  of  pur- 
purogallin  formed  wiien  there  was  excess  of  peroxidases 
was  in  direct  proportion  to  the  amount  of  hydrogen  peroxide, 
but  that  when  there  was  an  excess  of  hydrogen  peroxide  it 
was  in  direct  proportion  to  the  amount  of  peroxidase,  and 
that  both  these  materials  were  used  up  in  the  process  of 
oxidation.  This  may  be  interpreted  on  the  supposition  that 
in  the  formation  of  an  intermediary  product  these  substances 
react  upon  each  other  in  constant  proportions — a  point  dis- 
tinctly opposed  to  the  idea  of  a  true  ferment  reaction.  Other 
observations  along  similar  lines  have  been  made  by  the 
authors  named  in  connection  with  oxidation  of  hydriodic 
acid,  by  Czyhlarz  and  the  author  in  case  of  the  leukomal- 
achite  base, by  Herzog35  in  case  of  the  leuko  base  of  brilliant- 
green  and  in  case  of  vanillin.  It  would  be  premature,  how- 
ever, to  attempt  to  make  any  simple  relative  deductions  from 
all  these  complicated  matters.  It  is  to  be  kept  in  mind, 
too,  that  the  subject  is  further  complicated  by  the  possibility 
of  activation  of ' '  zymogens, ' ,36  and  that  for  the  present  there 
is  no  such  thing  as  ''isolation"  of  peroxidases,  although  re- 
cently at  least  we  have  learned  that  peroxidase  preparations 

a4Cf.  Bach,  Ber.  d.  deutschen  ehem.  Ges.,  43,  364,  1910. 

35  R.  O.  Herzog,  in  association  with  A.  Polotzky  and  A.  Meier  (Karlsruhe), 
Zeitschr.  f.  physiol.  Chem.,  73,  247,  258,  1911. 

36  A.  Bach,  Ber.  d.  deutsch,  chem.  Ges.,  40,  231,  1907. 


550  OXIDATION  FERMENTS 

may  be  freed  from  adnexed  catalases  and  oxygenases  by 
preparatory  treatment  with  pyrogallol.37 

Probably  C.  Oppenheimer 38  has  fully  and  correctly 
grasped  the  present  status  of  the  question,  when  he  states  as 
his  opinion  that  for  the  present  at  least  we  must  accept  the 
active,  thermolabile  peroxidases  as  ferments.  "For  the 
results  indicating  that  various  mixtures  of  salts  of  man- 
ganese and  of  iron  act  qualitatively  in  precisely  the  same 
way,  in  themselves  prove  nothing  against  an  enzymic  nature, 
as  similar  analogies  are  met  in  case  of  almost  all  ferments. 
Against  this  view,  above  all  should  be  recognized  the  fact 
that  we  can  demonstrate  veiy  active  peroxidases  which  do 
not  contain  manganese  or  iron.  True  oxidase  activity  really 
has  nothing  essential  to  do  with  these  salts,  even  though  sug- 
gestions to  the  contrary  perhaps  exist.  In  the  living  tissue 
provisions  would  seem  to  be  made  that  biological  catalysing 
agents,  ferments,  should  do  what  under  other  conditions 
inorganic  catalysers  are  able  to  do. ' ' 

Indophenoloxidases. — Attention  should  be  directed 
briefly  to  several  other  types  of  oxidases,  of  which  frequent 
mention  is  made  in  literature.  Among  these  first  are  indo- 
pkenoloxidases. The  synthesis  of  indophenol  from  para- 
phenylendiamine  and  a-naphthol, 

,NH2 

4\n  =  CioH60  +  2H20, 

was  first  made  use  of  by  Ehrlich  in  1885  in  his  classical  study 
of  physiological  oxygen  requirements  of  the  economy.  From 
the  standpoint  of  the  oxidizing  ferments  ßöhmann  and  Spit- 
zer, and  after  them  a  great  number  of  others,39  have  em- 
ployed the  reaction,  partly  for  histochemical  purposes.  Re- 
cently Vernon40  has  endeavored  to  perfect  a  quantitative 

37  A.  Kasanski  (Moscow),  Biochein.  Zeitschr.,  39,  64,  1911. 

38  C.  Oppenheimer,  1.  c,  p.  351. 

38  J.  Pohl,  Rosell,  Abelous  and  Biarnes  and  others.  Literature:  J.  H. 
Kastle,  1.  c,  pp.  100-103;  R.  Spanjer-Herford  (Braunschweig),  Virchow's 
Arch.,  205,  276,  1911;  W.  H.  Schultze  (Göttingen),  Ziegler  's  Beitr.,  45,  127, 
1909;    F.  Winkler,  1.  c. 


C6H4(NH2)2  +  610H7(OH)  +  02  =  C6h/ 


ALDEHYDASES  551 

method  for  the  determination  of  indophenoloxidase  in  ani- 
mal tissues.  His  results  indicate  that  those  mammalian  tis- 
sues, which,  according  to  Ehrlich,  are  highly  saturated  with 
oxygen  and  fail  to  change  indophenol  blue  when  injected 
intra  vitajn  (as  the  muscle  of  the  heart,  tongue  and  dia- 
phragm) are  apparently  rich  in  oxidases.  On  the  other 
hand,  tissues  which  reduce  intra  vitam  indophenol  blue  to 
indophenol  white  (as  the  glands  and  the  bulk  of  the  striated 
and  smooth  muscles)  prove  to  be  much  poorer  in  oxidase. 
The  richness  of  the  tissues  in  oxidases,  therefore,  runs 
parallel  with  the  grade  of  their  saturation  with  oxygen ;  and 
the  idea  necessarily  arises  that  we  may  be  dealing  with  a 
storage  of  oxygen  in  the  form  of  organic  peroxides  or  ' '  oxy- 
genases." Should  this  suspicion  prove  correct  this  reac- 
tion will  serve  as  a  test  for  oxygenases.  Indophenol  blue 
synthesis  fails  notably  in  the  tissues  of  animals  which  have 
been  killed  by  potassium  cyanide  (a  frank  ''ferment 
poison").41 

Purin  Oxidases. — Another  well  defined  group  of  oxidiz- 
ing ferments  is  composed  of  the  purin  oxidases.  These  are 
ferments  concerned  in  the  physiologically  important  oxida- 
tion catabolism  of  the  purin  bases  into  uric  acid  and  of  this 
latter  into  allantoin.  The  most  important  information  we 
possess  of  this  subject  was  presented  in  earlier  parts  of  these 
lectures  (Vol.  I  of  this  series,  p.  112,  Chemistry  of  the  Tis- 
sues; vide  supra,  p.  149)  and  need  not  be  further  dealt  with 
here. 

Aldehydases. — While  the  requirements  of  historical  jus- 
tice would  forbid  that  the  "aldehydases"  be  passed  in 
silence  we  here  come  nevertheless  into  a  comparatively  un- 
known field.  0.  Schmiedeberg  originally  discovered  that  if 
arterialized  blood  be  perfused  through  a  fresh  liver  or  lung 
and  salicylaldehyde  be  added,  salicylic  acid  is  formed  to 
some  extent. 

"H.  M.  Vernon  (Oxford),  Jour,  of  Physiol.,  42,  402,  1911;  43,  96,  1911; 
44,  150,  1912. 

41  H.  Raubitschek  ( Czernowitz ) ,  Wiener  klin.  Wochenschr.,  1912,  149. 


552  OXIDATION  FERMENTS 

Jaquet,  thereafter,  in  Schmiedeberg 's  laboratory,  was 
able  to  present  evidence  that  even  dead  tissue,  and  in  fact 
tissue  extracts  devoid  of  cells,  are  capable  of  oxidizing  alde- 
hyde. A  colorimetric  method,  based  on  the  red  color  which 
salicyclic  acid  gives  with  chloride  of  iron,  was  used  in  quan- 
titative determination  of  the  newly  formed  salicylic  acid  in 
these  studies.  The  distribution  of  aldehydases  in  animal 
tissues  was  thereafter  studied  by  a  number  of  authors.42 
Martin  Jacoby  elaborated  a  procedure  in  F.  Hofmeister 's 
laboratory  which  serves  to  separate  aldehydases  from  pro- 
teins by  a  combination  of  salting  out,  and  precipitation  by 
alcohol  and  by  uranyl acetate.  More  recently  Dony-Henault 
and  Mile,  van  Duuren43  have  submitted  the  problem  of 
aldehydases  to  a  renewed  study  and  have  convinced  them- 
selves that  there  were  many  important  technical  errors  in  the 
investigations  of  earlier  authors.  In  order  to  avoid  these, 
separation  of  the  salicylaldehyde  from  the  salicylic  acid 
should  be  completed  and  the  latter  estimated,  not  by  colori- 
metry,  but  by  gravimetric  method  (as  tribromphenol).  It 
was  found,  moreover,  in  correspondence  with  the  results  of 
Abelous  and  Aloy,44  that  oxidation  of  the  aldehyde  by  the 
"aldehydase"  occurs  best  in  the  absence  of  free  oxygen, 
and  that  a  given  amount  of  the  presumed  enzymic  solution 
is  able  to  oxidize  only  a  definite  amount  of  aldehyde.  This 
is  clearly  not  an  action  like  that  of  a  catalysator,  so  much 
so  that  the  ferment  nature  of  the  aldehydases  becomes  de- 
cidedly doubtful.  Perhaps  in  this  case,  too,  we  are  dealing 
with  the  action  of  peroxides  which  are  transferring  their 
oxygen  to  easily  oxidizable  substances.  The  lability  of  the 
' '  aldehydases ' '  would  not  interfere  with  such  a  view. 

Summary. — The  author  deems  it  time,  however,  to  lead 
his  readers  out  of  the  wilderness  of  academic  discussion 

42  Salkowski  and  Yamagiwa,  Abelous  and  Biarnös,  M.  Jacoby,  Rosell, 
Pfaundler,  Zarichelli  and  others;  cf.  Literature:  M.  Jacoby,  Ergebn.  d. 
Physiol.,  r,  233-234,  1902;    H.  M.  Vernon,  ibid.,  9,  214-216,  1910. 

43  0.  Dony-Henault  and  Mile.  J.  van  Duuren,  Bull.  Acad.  roy.  Belg.,  1907, 
537;    Arch,  intern,  de  Physiol.,  5,  39,  1907. 

**  J.  E.  Abelous  and  J.  Aloy,  C.  R.  Soc.  de  Biol.,  56,  222,  1904. 


SUMMARY  553 

which  has  been  indulged  in  all  too  long,  into  the  open,  and 
to  raise  the  question  as  to  precisely  what  effective  additions 
have  been  gained  from  all  this  for  our  knowledge  of  the 
physiological  processes  of  oxidation. 

This  much  can  be  said  in  summarizing:  In  the  tissues 
active  catalytic  agents,  the  " peroxidases,"  are  widely  dis- 
tributed; which  seem,  just  like  the  coloring  matter  of  the 
blood,  to  be  capable  of  conveying  the  oxygen  from  peroxides 
to  very  readily  oxidizable  substances.  We  find,  too,  in  the 
statements  bearing  upon  the  oxygenases,  the  aldehydases 
and  indophenoloxidases  occasion  for  assuming  that  there 
are  substances  in  the  tissues  charged  with  oxygen  which  are 
able  to  give  this  off  to  easily  oxidizable  matter ;  and  these  we 
may  in  a  measure  regard  as  peroxides.  But  that  is  all.  We 
do  not  know  whether  the  peroxidases  are  ferments  are  not. 
This  from  a  physiological  viewpoint  may  fundamentally  be 
a  matter  of  indifference,  because  at  any  rate  we  are  not 
able  to  define  clearly  the  characteristics  of  a  ferment.  For- 
erly  in  this  respect  we  were  perhaps  more  fortunate;  we 
frankly  had  no  idea  then  what  a  ferment  was;  we  were 
accustomed  to  being  satisfied  with  statements  that  ferments 
were  "coagulable"  substances  and  allowed  them,  con- 
fessedly or  by  inference,  to  drift  along  in  the  turbid  stream 
of  proteins,  that  is,  with  those  substances  with  which  we 
could  not  even  make  a  proper  beginning.  But  the  times 
have  changed;  and,  particularly  since  we  have  learned  to 
recognize  that  there  are  thermostable  ferments,  even  the 
finest  definitions  and  hypotheses,  with  which  science  of  the 
present  is  blessed  in  the  richest  measure,  cannot  deceive  us 
about  the  flimsiness  of  the  ferment  concept.  We  are  really 
doing  better  by  simply  stopping  and  by  holding  fast  to  what 
we  see;  and  that  is  the  effect  of  the  real  or  supposed  "fer- 
ments," the  catalytic  acceleration  of  reactions.  For  our 
question  it  is  quite  enough  from  a  physiological  standpoint 
for  us  to  know  that  in  the  tissues  there  are  some  sort  of 
catalytic  agents  of  unknown  nature  which  are  capable  of 
conveying  oxygen  to  easily  oxidizable  substances. 


554  OXIDATION  FERMENTS 

Now,  however,  we  come  directly  to  the  crucial  point  of 
the  whole  problem,  to  the  question  what  are  the  actual  oxida- 
tion functions  which  these  catalytic  agents  or  peroxidases 
accomplish. 

In  the  middle  of  the  past  century,  when  attention  was 
directed  to  the  catalytic  action  of  haemoglobin  and  it  became 
known  that  a  single  tiny  droplet  of  blood  could  change  a 
whole  big  vesselful  of  tincture  of  guaiac  like  magic  to  a 
beautiful  blue  color,  there  was  hope  that  we  were  near  to 
the  solution  of  the  great  enigma  of  how  the  economy  accom- 
plishes its  combustion  processes.  And  all  the  many  new 
color  reactions  of  the  peroxidases,  which  were  gradually 
found  out,  in  the  pomp  of  their  introduction  invariably  fur- 
nished new  food  for  this  hope,  and  invariably  seduced  re- 
search into  following  their  footsteps.  The  author  may  con- 
fess from  his  own  experience  that  he  was  never  able  to 
break  away  from  the  spell  of  suggestion  that  the  way  led 
hence  into  the  mysteries  of  the  vital  processes  of  oxidation, 
until  he  had  satisfied  himself  that  a  peroxidase,  however 
active  it  might  be,  could  never  break  down  a  single  milligram 
of  sugar.  There  is  not  the  least  basis  for  presuming  that  the 
oxidases  have  anything  whatever  to  do  with  the  vital  com- 
bustion of  proteins,  carbohydrates  and  fats.  The  glitter  of 
color-reactions  should  not  be  allowed  to  deceive  us  into 
believing  that  the  functions  of  the  oxidases  in  reality  are  of 
any  great  importance,  and  that  they  extend  beyond  a  very 
superficial  oxidation  especially  of  easily  seized  hydroxyl- 
containing  cyclic  compounds,  as  the  oxidation  of  formic  acid 
into  carbonic  acid,  etc.  This  is  not  to  say  that  such  oxida- 
tions are  necessarily  physiologically  unimportant.  The 
oxidation  of  the  purin  bases  into  uric  acid,  which  may  always 
be  attributed  to  oxidizing  ferments,  is  unquestionably  an 
important  process ;  and  so,  too,  the  oxidation  of  cyclic  pro- 
tein cleavage  products  into  melanins,  which  the  author  orig- 
inally proved,  and  which  is  now  after  thorough  study  of  the 
problem  from  many  sides  (cf.  Vol .  I  of  this  series,  pp.  526- 
528,  Chemistry  of  the  Tissues)  a  part  of  the  assured  posses- 


SUMMARY  555 

sions  of  physiology.  The  oxidases  are  capable  of  taking 
part  in  other  ways  in  the  catabolism  of  the  cyclic  complexes 
of  the  protein  molecule,  as  ( aside  from  their  role  as  * '  respira- 
tory enzymes"  in  the  vegetable  kingdom)  in  the  production 
and  destruction  of  Suprarenin,  and  in  all  sorts  of  detoxifying 
processes  in  the  animal  body.  The  study  of  the  oxidases 
has  not,  however,  brought  us  appreciably  nearer  to  the  final 
secrets  of  life. 

This  evidence  from  the  writer  may  seem  very  frank, 
coming  from  one  who  has  devoted  much  time  and  labor  upon 
the  oxidases  and  who  belonged  among  the  number  of  those 
who  ''rode"  the  oxidases;  it  would  undoubtedly  be  much 
more  pleasant  for  the  author  if  he  could  take  the  opposite 
position. 

"If  we  were  satisfied,"  thus  Battelli  and  Stern  conclude 
their  monograph,  "to  ascribe  to  the  oxidation  ferments  un- 
certain, ill-defined  characteristics,  we  might  also  accept  for 
them  unlimited  capacity  for  action,  and  assume  further  that 
they  effect  all  the  oxidations  in  process  in  the  economy.  In 
this  case,  however,  the  term  of  ferment  would  lose  all 
exact  meaning,  and  would  express  nothing  more  than  proto- 
plasm-activity or  cell-activity.  If  one,  however,  thinks  of 
the  oxidizing  ferments  as  constituting  a  well  defined  class 
of  enzymes  with  clearly  marked  characteristics  the  answer 
must  naturally  be  different.  We  will  then  be  forced  to  con- 
fess that  in  animal  tissue  we  know  of  no  single  agent  mani- 
festing the  peculiar  properties  of  the  oxidation  ferments  as 
they  have  thus  far  been  known,  that  possesses  the  ability  to 
induce  combustions  such  as  are  completely  carried  out  in  the 
animal  body,  and  to  reproduce  even  in  the  slightest  degree 
such  a  process  as  muscle  respiration,  for  example.  We  are, 
therefore,  not  justified  in  concluding  that  these  combustions 
are  caused  by  the  agency  of  oxidizing  ferments,  and  are 
compelled  to  acknowledge  that  the  mechanism  of  these  com- 
bustions is  thus  far  unknown. ' ' 45 

40  F.  Battelli  and  L.  Stern,  Ergebn.  d.  Physiol.,  12,  267-268,  1912. 


CHAPTER  XXIII 

CATALASES.    TISSUE  RESPIRATION 

CATALASES 

In  close  connection  with  the  discusssion  of  oxidizing 
ferments  the  present  lecture  will  be  devoted  first  to  the 
catalases.  Here,  too,  the  task  of  presentation  has  been  ma- 
terially lightened  by  the  fact  that  F.  Battelli  and  Miss  Stern, 
who  have  themselves  had  an  important  part  in  the  investiga- 
tion of  catalases,  have  critically  reviewed  all  the  literature 
upon  the  subject  in  a  recent  monograph.1  As  this  is  readily 
accessible  to  everyone  the  author  may  be  permitted  without 
going  into  details  to  satisfy  himself  with  sketching  in  the 
main  points. 

Definition  of  Catalases. — The  term  catalase  has  been  ap- 
plied to  ferments  which  are  able  to  break  up  hydrogen  per- 
oxide into  water  and  oxygen.  As  this  oxygen  is  in  molec- 
ular form,  and  inactive,  it  is  essential  to  clearly  differentiate 
the  catalases  from  the  oxidizing  ferments.  The  name 
"catalase"  was  originally  given  by  Low  (1901) ;  but  our 
recognition  of  these  substances  goes  back  much  farther. 
Even  Schönbein  was  concerned  with  them,  and  Thenard  as 
early  as  the  beginning  of  the  last  century  was  aware  of  the 
fact  that  tissues  of  the  most  varied  type,  as  well  as  blood 
fibrin  and  colloidal  noble  metals  are  capable  of  breaking  up 
hydrogen  peroxide.  The  phenomenon  was  sufficiently  con- 
spicuous to  prevent  the  catalases  from  fading  out  from  the 
perspective  of  physiological  research.  For  a  long  time  they 
were  confused  with  the  oxidizing  ferments,  an  error  first 
fully  corrected  by  the  investigations  of  Bach  and  Chodat. 
Senter,  who  obtained  the  catalase  of  the  blood  free  from 
haemoglobin,  proposed  the  name  "hasmase"  for  it;  but  such 

1  Literature  upon  Catalases :  C.  Oppenheimer,  Die  Fermente,  3d  ed.,  393- 
408,  1909;    F.  Battelli  and  L.  Stern,  Ergebn.  d.  Physiol.,  10,  531-597,  1910. 

556 


ACTIVITY  OF  CATALASE  PREPARATIONS  557 

a  title  is  superfluous  and  for  this  reason  has  had  but  little 
recognition. 

Demonstration. — F.  Battelli  and  L.  Stern  have  developed 
a  method  by  which  catalase  preparations  of  extremely 
marked  activity  may  be  obtained.  It  is  best  to  make  use  of 
horse-liver  or  beef-liver,  which  is  finely  divided,  agitated 
with  water  for  a  long  time  and  strained;  the  fluid  is  then 
precipitated  with  alcohol,  the  precipitate  separated  and 
redissolved  in  water,  and  the  solution  again  precipitated 
with  alcohol. 

Finally  there  is  obtained  an  amorphous  powder  of  almost 
incredible  catalyzing  power.  One  gram  is  capable  of  break- 
ing up,  in  ten  minutes  at  room  temperature,  four  kilograms 
of  hydrogen  peroxide  with  production  of  1300  liters  of 
oxygen.  The  preparation  is  quite  permanent  and  may  re- 
tain its  activity  unchanged  for  years.  It  is  well  known  that 
a  number  of  colloidal  metals  (as  platinum,  palladium, 
iridium  and  osmium)  are  also  capable  of  manifesting  ex- 
tremely powerful  catalyzing  influence.  It  is  calculated  that  a 
solution  of  osmium  containing  not  more  than  0.000,000,000,9 
gram  of  osmium  in  a  cubic  centimetre,  is  still  capable  of 
disintegrating  hydrogen  peroxide  appreciably.2  Neverthe- 
less Battelli  and  Stern  believe  (particularly  when  the  pre- 
sumably great  molecular  weight  of  the  catalase  is  taken 
into  consideration)  that  the  activity  of  their  catalase  is 
infinitely  greater  than  that  of  colloidal  platinum. 

Determination  of  Activity  of  Catalase  Preparations. — 
Determination  of  the  activity  of  a  catalase  preparation  may 
be  carried  out  in  different  ways.  A  given  quantity  of  tissue 
or  of  a  preparation  to  be  tested  may  be  allowed  to  act  upon 
a  known  quantity  of  hydrogen  peroxide,  and  after  a  certain 
time  the  amount  of  oxygen  formed  may  be  determined  or 
the  quantity  of  remaining  unchanged  peroxide  of  hydrogen 
may  be  estimated.     Or  a  dynamic  method  may  be  used,  by 

*  C.  Paal,  with  C.  Amberg  and  J.  Gerum,  Ber.  d.  deutsch,  ehem.  Ges.,  £0, 
2201,  2209,  1907. 


558  CATALASES 

measuring  the  height  to  which  a  column  of  mercury  is  raised 
by  the  oxygen  set  free  in  the  reaction,  that  is,  the  pressure 
against  which  the  catalase  is  able  to  act.3 

If  the  activities  of  two  catalase  solutions  are  to  be  com- 
pared the  "catalytic  power"  of  each,  in  the  author's  opin- 
ion, should  be  worked  out;  this,  too,  according  to  Victor 
Henri,4  being  the  only  proper  basis  for  comparison  of  the 
effective  ability  of  two  colloidal  metallic  solutions.  The 
reaction  velocity  of  hydrogen  peroxide  cleavage  is  de- 
termined according  to  the  equation  -—-  =  K(a  -  x) ,  t  being  the 

time,  a  the  amount  of  H202  at  zero  time,  x  the  amount  of 
H202  broken  up  in  the  time  t,  and  K  a  constant,  expressing 
nothing  more  than  that  the  amount  of  peroxide  of  hydrogen 
broken  up  in  any  fraction  of  time  is  in  direct  proportion  to 
the  amount  of  H202  at  the  moment  present.  A  simple  cal- 
culation gives  K  =  -^  log  — —  and  determines  the  value  of 

°  C  a  —  x 

the  constant  K.  If  in  addition  it  is  desired  to  obtain  the 
"catalytic  capacity,"  the  relation  of  the  amount  of  the 
metallic  solution  employed  to  the  quantity  of  hydrogen 
peroxide  must  also  be  taken  into  account. 

The  reaction  kinetics  of  catalase  action,  in  which  we 
have  an  example  of  a  "reaction  of  the  first  class,"  according 
to  Senter,  has  been  the  subject  of  study  at  the  hands  of  quite 
a  number  of  authors.5  It  is,  however,  impracticable  to 
enter  into  this  subject  here,  as  it  falls  entirely  in  the  domain 
of  physical  chemistry.  There  are,  too,  a  number  of  studies 
concerned  with  the  analogies  in  the  action  of  the  catalases 
and  of  colloidal  metals.  According  to  Liebmann  platinum 
catalase  may  perhaps  be  thought  of  as  consisting  primarily 
of  a  labile  oxygen  combination  of  platinum,  which  then  in- 
duces the  separation  of  the  peroxide  of  hydrogen  (Pt2  + 

3  W.  Lob  and  P.  Mulzer,  Biochem.  Zeitschr..  18,  339,  475,  1908. 

4  V.  Henri,  C.  R.  Soc.  de  Biol.,  60,  1041,  190G. 

6  Senter,  Raudnitz,  Lockemann,  Thies  and  Wichern,  Issajew,  Bredig  and 
Faitelowitz,  Euler,  Herlitzka,  Bach,  Iscoveso,  Loeb  and  Mulzer,  and  others;  cf. 
Literature:    Batelli  and  Stern,  1.  c. 


SIGNIFICANCE  OF  THE  CATALASES  55Ö 

02  =  2  Pt  0 ;  PtO  +  H202  =  Pt  +  H20  +  02 ) .  According 
to  Schade,6  however,  an  intermediate  oxide  formation  does 
not  occur,  and,  too,  the  phenomena  are  not  the  resultant 
manifestations  of  a  great  surface  development  as  believed, 
but  the  action  of  electrical  forces.  In  differentiation  between 
the  action  of  catalases  and  colloidal  metals  special  point  has 
been  made  of  the  difference  in  sensitiveness  to  high  tempera- 
tures, and  of  the  fact  that  the  action  of  catalases  is  strictly 
specific,  while  colloidal  metals  may  not  only  dissociate  perox- 
ide of  hydogen  but  may  also  blue  tincture  of  guaiac,  set  free 
iodine  from  hydriodic  acid,  etc.  An  interesting  analogy  is 
seen  in  their  behavior  with  cyanogen  which  paralyzes  cata- 
lases as  well  as  colloidal  metals,  and  in  each  instance  when 
it  is  driven  off  the  catalyzing  power  reappears.7 

Physiological  Significance  of  the  Catalases. — Important 
as  all  this  may  be  to  the  physical-chemist,  the  special  interest 
from  our  standpoint  lies  in  the  question  of  the  role  played  by 
the  catalases  in  the  play  of  interchange  of  forces  actively 
engaged  in  the  living  body. 

It  was  once  hoped  that  an  answer  to  this  question  would 
be  forthcoming  from  comparison  of  the  catalase  contents  of 
tissues  in  a  wide  group  of  physiological  and  pathological 
conditions ;  but  unfortunately  very  little  of  value  has  been 
attained. 

The  commonly  expressed  view  that  the  amount  of  cata- 
lases in  the  tissues  is  an  index  of  the  intensity  of  the  com- 
bustion processes  therein  is  shown  to  be  untenable  directly 
by  the  fact  that,  as  proved  by  Battelli  and  Stern,  the  tissues 
of  the  adder  and  toad  are  even  richer  than  the  tissues  of 
warm-blooded  animals  in  catalases;  and,  too,  muscles,  in 
spite  of  their  marked  respiratory  activity,  show  but  a  small 
proportion  of  catalases.8  The  presumption  of  a  parallelism 
between  the  proportions  of  catalases  and  peroxidases  in 

8H.  Schade   (Kiel),  Zeitschr.  f.  exper.  Pathol.,  1,  603,  1905. 

'  Cf.  0.  Low,  Centrabl.  f.  Bakteriol..  II,  21,  1,  1908;    T.  Bokorny,  ibid.,  193. 

8Cf.  also  E.  J.  Lesser  (Halle),  Zeitschr.  f.  Biol.,  J,9,  575,  1907. 


560  CATALASES 

tissues  has  as  little  foundation  as  the  assumption  of  an  an- 
tagonism between  them,  as  declared  by  the  younger  Ostwald 
on  the  basis  of  a  few  studies  on  lower  forms  of  animal-life, 
and  suggested  as  being  connected  with  the  problem  of 
phototropism.  So,  too,  the  assumption  of  this  last-men- 
tioned author,  that  catalase  plays  a  part  in  fertilization  proc- 
esses in  the  egg,  is  not  satisfactorily  established ;  and  there 
is  just  as  little  clear  evidence  from  the  sequential  study  of 
the  amounts  of  catalase  to  be  found  in  course  of  ontogenetic 
development.9  In  many  tissues  the  catalase  proportions  at- 
tain an  importance  at  very  early  stages  almost  comparable 
to  that  of  adult  tissues.  However,  Battelli  and  Stern  hold 
there  is  a  relation  between  the  marked  increase  in  catalases 
noticeable  a  few  days  after  birth  in  the  liver  of  guineapigs 
and  the  access  of  function  of  the  organ.  Along  the  same 
line  of  thought,  in  connection  with  a  loss  in  catalase  content 
in  livers  the  seat  of  fatty  degeneration  from  phosphorus 
poisoning,  a  coincident  increase  in  the  catalases  in  the  blood 
and  other  tissues  has  been  interpreted  as  a  "compensatory 
participation  by  the  tissues  in  catalase  production."  In 
the  author's  opinion,  however,  it  is  at  least  just  as  appropri- 
ate to  think  of  an  outflow  of  the  catalases  previously  fixed 
in  the  liver  and  their  distribution  by  the  bloodstream  to  the 
tissues.  There  does  not  seem  to  be  any  contradiction  to  this 
view  in  the  fact  that  catalase  experimentally  introduced  into 
the  bloodstream  is  soon  destroyed ;  it  is  altogether  possible 
that  artificially  isolated  catalase  is  less  well  protected 
against  destroying  agencies  than  that  which  passes  into  the 
circulation  when  the  liver  becomes  involved  in  fatty  degen- 
eration. Battelli  and  Stern  believe  that  the  ability  to  inac- 
tivate catalase  is  a  property  of  some  special  substance  which 
they  call  anticaialase.  Such  substance  cannot,  however,  be 
looked  upon  as  a  true  serum  antibody,  because  (according 

9  Battelli  and  S'tern,  1.  c. ;  L.  B.  Mendel  and  C.  S.  Leavenworth  (Yale  Univ., 
New  Haven),  Amer.  Jour,  of  Physiol.,  21,  85,  1908;  G.  Tallarico  (Pavia), 
Arch,  di  Farmacol.,  7,  535,  1908. 


SIGNIFICANCE  OF  THE  CATALASES  561 

to  de  Waele  and  Vandevelde)  nothing  of  the  kind  can  be 
recognized  either  in  normal  serum  or  in  the  serum  after 
immunization  by  the  ordinary  methods  employed  in  immun- 
ology.10 Battelli  and  Stern  also  assume  that  the  ability  of 
the  serum  and  of  extracts  of  many  tissues  to  prevent  the  de- 
structive effect  of  "anticatalase"  upon  catalase  to  be  due 
to  a  special  substance,  philo  catalase.  Activation  of  the 
"philocatalase,"  again,  is  held  as  the  function  of  another 
special  material,  the  "activator  of  philocatalase."  It  may 
be  remarked  in  connection  with  a  terminology  of  this  sort 
that  a  union  of  complicated  physical-chemical  factors 
can  be  thought  of  as  possibly  combining  to  bring  about 
the  effects  which  are  characterized  by  the  words  "cata- 
lase, anticatalase,  philocatalase  and  activator  of  catalase." 
If  the  purpose  be  to  employ  some  such  terms  for  the  un- 
known summation  of  this  sort  of  manifestations  of  energy 
by  undefined  physical-chemical  factors,  there  is,  of  course, 
no  objection  to  be  made;  but  there  is  no  reason  as  yet  for 
the  idea,  as  far  as  the  author  sees,  that  we  are  necessarily 
dealing  here  with  ' '  special  substances. ' ' 

In  connection  with  other  investigations  in  reference  to 
the  significance  of  catalase  action,  the  suggestion  that  these 
substances  are  somehow  concerned  in  the  conversion  of  fat xl 
is  quite  unproven.  In  contradiction  to  the  assumption  of 
Low  that  the  catalases  are  intended  to  protect  the  living  cells 
against  the  toxic  action  of  the  hydrogen  peroxide  supposed 
to  be  produced  in  the  processes  of  oxidation,  Bach  and  Cho- 
dat  have  brought  forward  the  fact  that  this  substance  is  not 
especially  toxic  (quite  a  number  of  the  lower  plants  thrive 
very  well  in  a  one  per  cent,  solution  of  peroxide  of  hydrogen) . 
Although,  again,  others  have  suggested  the  belief  that  the 
catalases  supposedly  are  protective  to  the  organism  against 

10  H.  de  Waele  and  A.  J.  J.  Vandevelde  ( Ghent ) ,  Biochem.  Zeitschr.,.  9,  264, 
1908. 

11  H.  Euler   (Stockholm),  Hofmeister's  Beitr.,  7,  1,  1906. 

36 


562  CATALASES 

the  peroxidases,12  it  should  be  stated  in  contravention  that 
Bach  and  Chodat  hold  that  in  setting  up  a  system  of  H202  + 
peroxidase  -j-  oxidizable  substance  +  catalase,  the  catalase 
can  not  disturb  in  the  least  the  oxidizing  action  of  the  per- 
oxidase, but  breaks  up  only  the  remnant  of  peroxide  of 
hydrogen,  which  was  not  consumed  by  the  peroxidase.13 

Finally,  contrary  to  the  belief  of  Jolles  14  and  Ewald  15 
that  catalases  are  able  to  facilitate  the  separation  of  oxygen 
from  oxyhemoglobin,  it  may  be  regarded  as  proved  (from 
the  studies  of  E.  v.  Czyhlarz  and  the  author)16  that  power- 
fully active  catalases  are  incapable  of  accelerating  the  oxida- 
tion of  ammonium  sulphide  by  oxyhemoglobin,  as  well  as 
of  phenolphthalin  by  hydrogen  peroxide  in  the  presence  of 
hsematin.  There  is,  therefore,  no  basis  whatever  for  assum- 
ing an  oxidizing  power  for  the  catalases. 

In  reviewing  the  above,  it  must  in  honesty  be  acknowl- 
edged that  we  not  only  know  nothing  positive  about  the 
physiological  operation  of  the  catalases,  but  also  that  we  do 
not  even  know  whether  they  have  any  important  physio- 
logical significance  at  all,  and  whether  they  may  not  perhaps 
be  altogether  accidental  and  non-essential.  Each  year  in 
his  lectures  the  author  is  in  the  habit  of  presenting  before 
his  students  the  experiment  in  which  a  few  drops  of  blood 
are  placed  in  a  large  beaker  glass  and  drop  by  drop  hydro- 
gen peroxide  is  added.  The  audience  wonders  and  is 
pleased  as  the  reaction  fiercely  goes  on  with  a  violent  and 
voluminous  production  of  froth ;  and  the  lecturer  also  won- 
ders and  is  pleased  at  the  remarkable  and  imposing  mani- 
festation of  nature.  But  does  this  say  that  the  phenomenon 
has  any  part  in  the  vital  processes  ?  May  it  not  be  thought 
that  physiologists  are  "obsessed"  by  the  catalases  by  the 
very  fact  of  their  imposing  appearance  ?     The  author  would 

12  A.  Herlitzka,  Rendic.  Accad.  dei  Lincei,  16,  473,  1907,  and  earlier  papers. 

13  Cf.  Battelli  and  Stern,  1.  c.,  p.  594. 

14  A.  Jolles,  Fortschr.  d.  Med.,  22,  1229,  1904. 

15  W.  Ewald,  Pflüger's  Arch.,  116,  334,  1907. 

1S  E.  v.  Czylharz  and  0.  v.  Fürth,  Hofmeister's  Beitr.,  10,  389,  1907. 


CARDINAL  AND  ACCESSORY  RESPIRATION        563 

not  be  mistaken!     This  is  not  to  say  that  this  is  actually 
the  case ;  but  the  author  believes  that  it  is  possibly  true. 

TISSUE  RESPIRATION 

In  the  failure  of  the  oxidases  and  catalases  to  fulfil  the 
hopes  that  were  rested  upon  them,  we  have  endeavored 
in  other  lines  to  approach  the  problem  of  the  combustion 
processes  of  the  living  body. 

Cardinal  Respiration  and  Accessory  Respiration. — In 
the  first  place  the  systematic  studies  of  F.  Battelli  and  L. 
Stern  should  receive  attention.  These  authors  make  a  dif- 
ferentiation between  the  cardinal  respiration  and  the  acces- 
sory respiration  of  animal  tissues.  The  former  is  by  far 
the  more  important,  although,  too,  much  the  more  labile 
process,  and  involves  the  life  of  the  cells.  In  many  tissues 
(especially  richly  in  muscles)  there  is  an  agent  of  unknown 
nature,  " pnein,"  which  is  capable  of  increasing  the  cardinal 
respiration  of  the  tissue  as  this  becomes  progressively 
weaker  after  the  death  of  the  animal.  By  washing  out  the 
"pnein"  for  the  most  part  the  tissues  thus  freed  manifest  a 
very  low  respiratory  activity,  but  by  introduction  of  pnein 
this  can  be  very  distinctly  increased.  The  pnein  is  looked 
upon  as  an  "activator  of  the  fundamental  respiratory 
process,"  but  has  no  influence  upon  the  accessory  respira- 
tion. It  is  apparently  a  substance  resistive  to  boiling  tem- 
perature, to  pepsin  and  trypsin ;  soluble  in  water  and  dialy- 
sable,  slightly  soluble  in  alcohol,  insoluble  in  ether.  In  va- 
rious animal  tissues  there  is  also  an  agent  which  decreases 
the  cardinal  respiration ;  it  is  known  as  "  antipnewnin." 

While  the  cardinal  respiration  is  not  dependent  upon 
agencies  of  ferment  type,  apparently  the  accessory  respira- 
tion is.  The  intake  of  oxygen  in  the  latter  is  not  under  all 
conditions  accompanied  by  the  formation  of  carbonic  acid. 
While  the  cardinal  respiration,  as  stated,  is  of  very  labile 
nature,  the  accessory  respiration  may  remain  unchanged  in 
tissues  for  twenty-four  hours  or  more.     If  a  tissue  is  finely 


564  TISSUE  RESPIRATION 

ground  up  and  treated  with  alcohol  or,  better,  with  acetone, 
and  quickly  dried  in  vacuo  over  sulphuric  acid,  a  tissue 
powder  may  be  obtained  which  is  capable  of  taking  up  no 
inconsiderable  amount  of  oxygen  and  of  producing 
carbonic  acid. 

The  tissue  respiration  is  deteriorated  by  poisons  like 
prussic  acid,  oxalates  and  fluoride  of  sodium;  is,  on  the 
other  hand,  increased  by  slight  alkaline  concentrations.  In- 
troduction of  glucose,  citric  acid,  malic  acid  or  fumaric  acid 
increases  very  decidedly  the  tissue  gas  interchange  at  times. 
These  substances  moreover  are  capable  of  oxidizing  ethyl 
alcohol  to  aldehyde  and  the  latter  into  acetic  acid,  and  of 
converting  succinic  acid  into  malic  acid  (COOH.HC2.CH2. 
COOH— KX)OH.CH(OH).CH2.COOH).17 

Experiments  along  similar  lines  have  been  conducted  by 
Olav  Hanssen  in  F.  Hofmeister 's  laboratory.18  Ground-up 
tissue  was  kept  in  agitation  in  flasks  at  body  temperature, 
oxygen  being  conducted  through  the  medium ;  and  the  gas 
passing  off  was  tested  for  its  content  of  carbonic  acid.  The 
experiments  of  Harden  and  Maclean  tend  in  the  same  di- 
rection, indicating  that  isolated  tissue  under  the  conditions 
described  do  not  produce  any  more  carbonic  acid  from  sugar 
in  an  atmosphere  of  oxygen  than  in  a  nitrogen  or  hydrogen 
atmosphere.19  Buytendyk  in  turn  sealed  the  tissue  in  a 
measured  amount  of  special  salt  solution  and  tested  the 
diminution  of  oxygen  content  of  the  latter ;  under  these  con- 
ditions, too,  the  cardinal  respiration  could  be  readily  distin- 
guished from  the  accessory  respiration.20  Finally  Lussana 
performed  the  same  sort  of  experiments  under  more  nearly 

17  F.  Battelli  and  L.  Stern,  Biochem.  Zeitschr.,  21,  488,  1909;  28,  145,  1910; 
30,172,1910;  31,  478,  1911;  33,315,1911;  36,114,1911;  Ergebn.  d.  Physiol., 
12,  215-216,  1912. 

18  O.  Hanssen  (F.  Hofmeisters  Lab.,  Strassburg),  Biochem.  Zeitschr.,  22, 
433,  1909. 

"  A.  Harden  and  H.  Maclean,  Jour,  of  Physiol.,  Jt3,  34,  1911. 
20  F.  J.  J.  Buytendyk  (Utrecht),  VIII  Int.  Physiol.  Kongr.,  Vienna,  Sept. 
27-30,  1910. 


REDUCING  TISSUE  COMPONENTS  565 

"  physiological "  conditions,  using,  besides  physiological 
salt  solution,  also  blood  serum  and  blood  itself.  In  this  case 
respiration  was  less  marked  in  homologous  serum  than  in 
physiological  salt  solution.  After  extirpation  of  the  kidneys 
substances  are  thought  to  accumulate  in  the  blood  having 
an  unfavorable  influence  upon  the  tissue  respiration.21 

Reducing  Tissue  Components. — Another  group  of  phe- 
nomena usually  regarded  as  connected  with  the  processes  of 
tissue  respiration  involve  the  reducing  power  of  tissues  and 
tissue  constituents. 

Paul  Ehrlich,  in  the  course  of  his  studies  of  the  oxygen 
requirement  of  the  body,  injected  methylene  blue  into  ani- 
mals. This  coloring  material  is  changed  by  reduction  into 
its  leukocombination ;  by  oxidation  the  latter  may  be  re- 
turned into  the  original  dye.  It  may  be  easily  noted  in  the 
animals  thus  injected  with  methylene  blue  in  which  of  the 
tissues  the  blue  dye  has  retained  its  color  and  in  which  it 
has  been  decolorized,  to  be  restored  when  atmospheric  air 
gains  access  to  it.  The  reduction  of  the  methylene  blue  in 
the  tissues  can  be  followed  by  titration  with  titanium 
chloride.22  A  number  of  other  examples  of  reducing  actions 
have  been  met  from  time  to  time  in  the  body ;  as  the  reduc- 
tion of  nitrates  to  nitrites,  of  arsenic  acid  to  arsenious  acid, 
of  nitrobenzol  to  aniline,  of  iodates  to  iodides,  of  tellurates 
to  tellurium,  of  sulphur  to  sulphuretted  hydrogen,  etc.23 

Such  reductions  have  been  looked  on  by  many  authors  as 
predicating  the  existence  of  reducing  ferments  (reductases). 
Thus  deRey-Peilhade  ascribed  the  reduction  of  finely  emulsi- 
fied sulphur  into  sulphuretted  hydrogen,  which  a  number  of 
tissues  are  capable  of  inducing,  to  a  ferment,  " philothion," 

aF.  Lussana  (Bologne),  Arch,  di  Fisiol.,  6,  269,  1909;  8,  239,  1910;  9,  575, 
1911. 

12  H.  Wichern  (Leipzig),  Zeitschr.  f.  physiol.  Chem.,  57,  3G5,  1908. 

23  Literature  upon  Reducing  Actions  of  the  Tissues:  A.  Heffter,  Mediz. 
naturw.  Arch.,  1,  82-103,  1907;  T.  Tunberg,  Ergebn.  d.  Physiol.,  11,  328-344, 
1911. 


566  TISSUE  RESPIRATION 

the  physiological  function  of  which  he  supposed  to  consist 
in  the  reduction  of  oxygen  coming  into  the  tissues  into 
water.24 

All  these  observations  have,  however,  appeared  in  an 
entirely  new  light  since  Heffter 25  subjected  them  to  syste- 
matic study.  It  was  shown  that  certainly  in  large  part  the 
phenomena  which  are  connected  with  the  autoxydizability 
and  reducing  power  of  protoplasm  are  occasioned  by  the 
presence  of  sulphydril  groups  (SIT).  The  beautiful  violet 
color  struck  by  sodium  nitroprusside  with  alkali  sulphides 
may  be  traced  to  the  sulphydril  groups.  Arnold  was  able 
to  show  that  a  number  of  proteins  give  the  reaction,  and 
that  it  can  also  be  due  in  tissue  extracts  no  longer  containing 

CH2.SH 
protein  by  the  presence  of  cystein,26   ch.nh2.    The  nature  of 

COOH 
the  changes  and  the  mode  of  action  by  which  sulphydril 
groups  react  with  oxygen  is  illustrated  in  the  autoxidation  of 
thiophenol  (C6H5.SH),  which  takes  up  oxygen  when  shaken 
with  air,  peroxide  of  hydrogen  being  produced  as  an  inter- 
mediate material.27  Heffter  would  represent  the  reaction  of 
the  sulphydril  groups  in  the  tissues  accordingly  by  the  fol- 
lowing schema : 

R-S  R— S 

2R.SH  +  02  =         |  +  H202 ;  2R.SH  +  H202  =         |  +  2H20. 
R-S  R-S 

It  is  possible  to  fancy  that  the  transformation  of  cystein 
into  cystin  (occurring  spontaneously  and  at  low  tempera- 
ture) may  perhaps  take  place  in  this  manner. 

MCf.  also  D.  F.  Harris  (Birmingham),  Biochem.  Jour.,  5,  143,  1910;  A. 
Montuori,  Memoirie  della  Soc.  ital.  delle  Scienze,  serie  III,  16,  237,  1910;  Arch, 
ital.  de  Biol.,  55,  197,  1911. 

25  A.  Heffter,  1.  c,  and  Hofmeister's  Beitr.,  5,  213,  1904;  Arch.  f.  exper. 
Pathol.,  Schmiedeberg  Festschr.,  253,  1908;  B.  S'trassner  (Heffter'a  Lab.), 
Biochem.  Zeitschr.,  29,  295,  1910. 

26  V.  Arnold  (Lemberg),  Zeitschr.  f.  physiol.  Chem.,  70,  300,  314,  1911. 

27  According  to  Engler  and  Broniatowski. 


OXYGEN  CONSUMPTION  IN  THE  BLOOD  567 

To  quote  Heffter  :2S  "The  principal  results  of  the  above 
investigations  may  be  summarized  by  stating  that  the  reduc- 
tions of  methylene  blue,  of  sulphur,  tellurium  oxide,  etc.,  by 
animal  and  vegetable  cells  are  not  the  effects  of  enzyme 
action.29  They  are  to  be  referred  to  the  presence  of  proteid 
substances  which  contain  one  or  more  sulphydril  groups. 
The  readily  detached  hydrogen  of  this  group  may,  as  shown 
by  the  behavior  of  cystein  and  similar  compounds,  exert 
strong  reducing  action.  It  is  also  capable  of  directly  uniting 
with  molecular  oxygen.  For  this  reason  the  sulphydril  com- 
pounds of  the  tissues  are  autoxidizable.  Herein,  at  least  in 
part,  may  be  seen  an  explanation  of  the  affinity  of  the  cells 
for  oxygen  as  well  as  of  the  possibility  of  formation  of 
hydrogen  peroxide."  Certain  tissue  constituents  may  act 
in  this  connection  as  catalyzators  and  accelerate  the  reduc- 
tion brought  about  by  the  sulphydril  groups. 

One  would  be  going  too  far,  however,  to  refer  all  reduc- 
tions in  the  tissues  to  the  influence  of  the  sulphydril  groups. 
The  reduction  of  nitrates  and  of  nitrobenzol,  for  example, 
seems  to  rest  on  a  different  basis.30  Attention  has  been 
called,  especially  by  the  investigations  of  S.  Fränkel  and  his 
associates,31  to  the  strong  reducing  action  of  unsaturated 
tissue  phosphatids.  However,  as  we  possess  no  basis  at 
the  present  time  for  holding  that  reductions  of  this  kind  are 
actually  concerned  in  the  vital  combustions  it  seems  alto- 
gether too  early  to  attempt  to  base  "A  Theory  of  Tissue 
Eespiration  Through  Intermediary  Bodies"  on  this  status. 

Oxygen  Consumption  in  the  Blood. — As  a  sequel  to  the 

28  A.  Heffter,  Med.  Naturw.  Arch.,  1,  103,  1907. 

29  Abelous,  Iscoveso  and  others  have  likewise  expressed  doubt  as  to  the 
enzymic  nature  of  the  reductases. 

ao  Cf.  also  A.  Bach;  Arch.  Sc.  nat.  GenSve,  82,  27,  1911,  cited  in  Centralbl. 
f.  d.  ges.  Biol.,  1911,  No.  2555;    Biochem.  Zeitschr.,  31,  443,  1911. 

31  S.  Fränkel  and  A.  Nogueira,  Biochem.  Zeitschr.,  16,  378,  1909;  S.  Fränkel 
and  L.  Dimitz,  ibid.,  21,  337,  and  Wiener  klin.  Wochenschr.,  1910,  No.  51; 
S.  Fränkel,  Dynamische  Biochemie,  pp.  31-34,  1911. 


568  TISSUE  RESPIRATION 

problem  of  the  reducing  constituents  of  the  tissues  we  may 
next  take  up  the  question  of  the  consumption  of  oxygen  in 
the  blood.  Although  earlier  recognized  that  blood  which 
has  been  standing  for  a  long  time  becomes  impoverished  in 
oxygen,  it  was  shown  by  the  studies  of  Eduard  Pflüger  and 
of  Alexander  Schmidt  in  the  sixties  that  not  inconsiderable 
amounts  of  oxygen  may  disappear  from  the  blood  withdrawn 
from  a  vein  with  coincident  production  of  carbonic  acid. 
Then  when  the  search  was  made  for  the  reducing  substances 
which  it  was  presumed  must  necessarily  be  particularly  rich 
in  the  blood  in  asphyxia  it  was  quickly  realized  that  only  the 
blood  corpuscles,  but  not  the  serum  of  the  asphyxia  blood, 
were  capable  of  fixing  oxygen,  and  that  the  lymph  of  asphyxi- 
ated animals  was  also  free  from  reducing  substances.32 
More  recently  the  question  of  oxygen  consumption  in  the 
blood  has  been  systematically  studied  particularly  by  P. 
Morawitz  and  his  pupils.  They  confirm  the  view  that  even 
in  condition  of  extreme  asphyxiation  there  is  no  transfer  of 
substances  with  affinity  for  oxygen  from  the  tissues  to  the 
blood  stream,  which  would  be  at  all  capable  of  oxidation  in 
the  mere  presence  of  oxygen.  The  oxidation  processes 
which  take  place  in  the  blood  are  obviously  connected  with 
the  blood  cells.  While  the  blood  corpuscles  of  adult  human 
beings  manifest  only  a  minor  oxygen  consumption,  the 
erythrocytes  of  young  individuals  exhibit  this  feature  to  a 
highly  important  degree.  The  blood  platelets,  too,  seem  to 
have  something  to  do  with  oxygen  consumption.  It  is  a  very 
striking  point  that  the  blood  of  rabbits  rendered  ana?mic  by 
a  subchronic  Phenylhydrazin  poisoning  should  (in  contrast 
with  normal  blood)  show  in  vitro  a  marked  oxygen  consump- 
tion and  carbonic  acid  formation.  This  was  proved  to  be 
independent  of  the  serum  and  the  leucocytes,  and  was  due  to 
the  numerous  young  erythrocytes  in  the  blood;    the  con- 

82 Literature:  N.  Zuntz,  Hermann's  Handb.  d.  Physiol.,  4",  92,  1882. 


LIVING  AND  DEAD  PROTEIN  569 

sumption  of  oxygen  apparently  serves  as  an  index  of  the 
intensity  of  the  regenerative  processes  in  the  blood.33 

There  is  an  interesting  point  in  the  fact  that  the  ability 
of  the  body  to  reduce  atoxyl  to  a  trypanocidal  substance 
(which  is  in  immediate  relation  with  its  therapeutic  effects) 
is,  according  to  the  studies  of  Levaditi  and  Yamanouchi, 
evidently  connected  with  the  blood.34 

The  fact  that  the  iron-bearing  red  corpuscles  are  the  ele- 
ments which  dominate  the  consumption  of  oxygen  by  the 
blood  seems  to  have  given  fresh  reason  for  the  belief,  which 
for  the  last  hundred  years  has  been  constantly  recurring, 
of  the  importance  of  iron  in  connection  with  animal  oxida- 
tions. Yet  it  is  clear  that  this  factor  may  be  overestimated, 
when  it  is  recalled  that  sea-urchin  spermatozoa,  which  are 
very  closely  analogous  to  young  red  blood  cells  in  this  matter 
of  oxygen  consumption,  have  been  found  to  contain  no  iron.35 

In  the  end  we  invariably  come  back  to  the  recognition  of 
the  fact  that  the  power  of  conducting  the  vital  combustion 
processes  is  an  innate  peculiarity  and  function  of  living 
protoplasm,  a  truism  which  in  reality,  to  be  honest,  is  strictly 
not  something  which  we  know  but  rather  a  standing  witness 
to  our  lack  of  knowledge,  a  fact  which  cannot  be  hidden  by 
the  most  brilliant  definitions  and  hypotheses  of  natural 
philosophy  except  in  the  most  pitiful  manner. 

Living  and  Dead  Protein. — We  contrast  the  "living  pro- 
tein" of  Pflüger  (the  "active  protein"  of  Low  or  "biogen" 
of  Verworn)  with  the  ordinary  "dead"  protein.  The  living 
protein  is  held  to  be  distinguished  by  special  lability,  as  to 
the  cause  of  which  different  hypotheses  have  been  promul- 
gated.    Pflüger  believed  that  the  carbon  and  nitrogen  atoms 

33  P.  Morawitz,  Arch.  f.  exper.  Pathol.,  60,  298,  1909;  Deutsch.  Arch.  f. 
klin.  Med.,  100,  191,  1910;  103,  253,  1911;  S.  Itami  (Med.  Clinic,  Heidelberg), 
Arch.  f.  exper.  Pathol.,  62,  93,  1910;  O.  Warburg  (Med.  Clinic,  Heidelberg), 
Zeitschr.  f.  physiol.  Chem.,  69,  452,  1910;    M.  Onaka,  ibid.,  11,  193,  1911. 

34  T.  Yamanouchi,  C.  R.  Soc.  de  Biol.,  68,  1910. 

85  E.  Masing  (Zoolog.  Station,  Naples,  and  Med.  Clinic,  Heidelberg), 
Zeitschr.  f.  physiol.  Chem.,  66,  262,  1910. 


570  TISSUE  RESPIRATION 

in  his  living  protein  combine  to  form  cyanogen  radicals, 
which  are  entirely  absent  in  the  "dead"  protein.  The  prin- 
cipal argument  advanced  in  support  of  this  view,  to  the 
effect  that  disintegration  products  of  the  living  protein  like 
urea,  creatin  and  nuclein  bases  in  some  instances  contain 
the  cyanogen  radical,  and  in  some  instances  can  be  produced 
artificially  from  cyanogen  compounds,  seems  to  the  author 
decidedly  open  to  question.  Verworn  in  his  biogen  theory 
has  formulated  views  which  are  somewhat  better  defined. 
"By  the  intramolecular  addition  of  inspired  oxygen  the 
biogen  molecule  finally  arrives  at  the  maximum  of  its  readi- 
ness to  undergo  decomposition,  so  that  only  very  slight  influ- 
ences are  required  to  bring  about  the  union  of  the  oxygen 
atoms  with  the  carbon  of  the  cyanogen.  The  material  of  the 
non-nitrogenous  groups  of  atoms  afforded  by  the  explosive 
decomposition  of  the  biogen  molecule  can  easily  be  regener- 
ated by  the  residue  of  the  biogen  molecule  from  the  carbo- 
hydrates and  fats  that  are  present  in  the  living  substance. 
If,  finally,  the  living  substance  dies,  with  the  absorption  of 
water,  the  labile  cyanogen-like  compound  of  nitrogen  passes 
over  again  into  the  more  stable  condition  of  the  ammonia 
radical,  the  nitrogen  uniting  with  the  hydrogen  of  the 
water."36 

On  the  other  hand  for  several  decades  Low  has  main- 
tained the  hypothesis  that  the  labile  character  of  living 
protoplasm  depends  upon  a  coexistence  of  aldehyde  groups 
and  amino  groups.37  The  basis  assumed  for  this  hypothesis 
is  somewhat  as  follows :  First,  the  fact  that  aminoaldehydes, 

CH2.NH2  ,.11 

as  the  compound  I  ,  are  very  labile  substances ;  again, 

COH 

living,  in  contrast  to  dead,  protoplasm  may  be  held  to  show 
its  aldehyde  nature  in  its  ability  to  reduce  dilute  alkaline 
silver  solutions ;   and  finally  those  substances  which  either 

38  M.  Verworn,  Allgem.  Physiol.,  2d  ed.,  p.  489,  1897;  Lee's  Amer.  Ed., 
p.  483, 1899. 

37  O.  Low,  Die  chemische  Energie  der  lebenden  Zellen,  2d  ed.,  Stuttgart,  1906. 


RESPIRATION  OF  ISOLATED  ORGANS  571 

react  with  aldehyde  groups  (as  hydrocyanic  acid,  hydrazine, 
hydroxylamine,  semicarbazide)  or  fix  amino  groups  (as 
formaldehyde  and  nitrous  acid)  are  all  protoplasmic  poisons. 
In  opposition  to  all  such  hypotheses  it  must  be  said  that  since 
Franz  Hofmeister  brought  to  light  a  typical  protein  like 
eggalbumin  in  crystalline  form,  the  conception  of  a  "  living 
protein"  has  lost  all  its  original  significance  for  the  chemist 
(cf.  Vol.  I  of  this  series,  p.  3,  Chemistry  of  the  Tissues).  It 
is  not  in  the  structure  of  the  protein  molecule  but  in  the 
organization  of  the  cell  that  the  great  wall  looms  up  from 
which  unfortunately  it  can  still  be  called  to  us :  "  Nach 
drüben  ist  die  Aussicht  uns  verrant."  "We  would  not  con- 
tinue: "Thor,  wer  dorthin  die  Augen  blinzend  richtet," 
but  hope  and  trust  that  science,  forging  onward  in  triumph, 
will  some  day  force  a  breach  in  this  wall  as  well.  That, 
however,  this  may  come  to  pass  from  theoretical  speculation 
the  author  does  not  believe,  however  much  he  may  otherwise 
prize  intellectual  argument  and  however  highly  he  may  ap- 
preciate the  heuristic  value  of  a  hypothesis  as  a  precedence 
for  investigation. 

Methods  of  Study  of  the  Respiration  of  Isolated  Organs. 
— Unfortunately  in  physiology  it  is  often  necessary  to  be 
satisfied  to  follow  to  some  length  phenomena  which  we  do 
not  understand  and  which  we  cannot  explain.  This  is  ex- 
emplified by  the  fact  that,  although  we  have  scarcely  even 
approached  the  real  nature  of  the  combustion  processes  in 
the  living  body,  we  have  learned  at  any  rate  to  perform 
quantitative  investigations  of  the  respirations  of  individual 
organs.  Experimentation  along  these  lines  dates  as  far 
back  as  to  Carl  Ludwig  and  his  school.  Although  until  a 
few  years  ago  it  was  possible  only  indirectly  to  determine  in 
isolated  cases  from  studies  of  the  energy  transformations  of 
the  general  body  what  share  in  these  the  activities  of  indi- 
vidual organs  take,  to-day  this  can  be  directly  accom- 
plished. 

This  may  be  done  by  studying  the  changes  in  the  composi- 


572  TISSUE  RESPIRATION 

tion  of  the  blood  gas  of  the  artificially  perfused  organ  in  situ, 
taking  samples  of  the  blood  from  the  artery  and  from  the 
vein  for  testing.  Of  course,  the  amount  of  blood  passing 
through  the  organ  in  a.  unit  of  time  must  be  known. 
Formerly  it  was  customary  to  make  use  of  Ludwig 's 
stromuhr  for  this  purpose.  At  present  Brodie's  method  is 
found  an  improvement,  the  organ  being  enclosed  her- 
metically in  a  capsule,  the  vein  pinched  shut  for  a  measured 
length  of  time  and  the  blood  at  the  same  time  allowed  to  flow 
on  in  the  artery;  the  increase  in  volume  in  the  organ  thus 
occasioned  is  measured  oneometrically. 

Blood  Gas  Analysis,  Bar  croft  and  Haldane's  Method. — 
The  methods  to  be  considered  for  analysis  of  the  gases  of  the 
blood  in  studies  of  this  sort  are  in  part  based  upon  the 
use  of  Pflüger 's  mercury  pump,  in  part  upon  the  application 
of  Haldane's  method  of  determining  the  oxygen  in  the  blood 
by  driving  it  out  of  the  blood  by  means  of  potassium  ferri- 
cyanide  after  laking.  Anyone  desiring  fuller  details  of  the 
method  may  be  referred  to  the  excellent  paper  of  Joseph 
Barcroft,38  in  which  the  technic  of  determinations  of  this 
sort  is  set  forth  with  the  greatest  completeness.  As  one 
cubic  centimetre  of  blood  is  sufficient  for  the  estimation  by 
the  Barcroft-Haldane  method  of  gas  analysis,  it  has  the 
advantage  of  enabling  one  to  work  with  small  organs  and  to 
make  comparisons  of  them.  The  apparatus  consists  of  a 
small  glass  receptacle  into  which  by  means  of  a  three-way 
cock  the  sample  of  blood  to  be  analysed  is  introduced  directly 
from  the  vessel  of  the  animal.  The  receptacle  is  so  ar- 
ranged that  the  oxygen  of  the  sample  of  blood  is  set  free  by 
potassium  ferricyanide,  and  the  increase  of  pressure  thus 
produced  is  measured  by  a  manometer.  A  similar  pro- 
cedure, in  which,  instead  of  the  ferricyanide,  tartaric  acid  is 
used,  serves  for  the  determination  of  the  carbonic  acid  by 
freeing  it  from  its   alkaline   combinations.      The  oxygen 

38  J.  Barcroft  (Cambridge),  Ergebn.  d.  Physiol.,  9,  763-794,  1908. 


COHNHEIM'S  RESPIRATION  APPARATUS  573 

measurement  for  one  cubic  centimetre  of  ox  blood  or  cat's 
blood,  for  which  hamioglobinometric  estimation  had  given  an 
average  result  of  0.197  ccm.,  was  with  this  apparatus  0.198; 
in  one  cubic  centimetre  of  a  soda  solution  of  known  content 
determination  yielded,  instead  of  0.421  cubic  centimetres  of 
C02,  mean  results  of  0.420  and  0.423.  These  results  indicate 
an  almost  incredible  exactness,  and  it  is  certainly  not  too 
much  to  say  that  this  method  of  Barcroft  and  Haldane 
should  be  included  among  the  most  brillant  achievements 
thus  far  accomplished  by  precise  work  in  the  field  of  physio- 
logical technic. 

In  the  study  of  tissue  respiration  occasionally  there  may 
be  occasion  for  analyzing  the  gases  contained  in  salt  solu- 
tions. Thus,  for  instance,  Vernon  transfused  excised  mam- 
malian kidney  with  Ringer's  solution,  and  thereafter 
analyzed  the  latter  for  its  content  of  gas.  The  capillary  tube 
method  of  gas  analysis  employed  in  such  studies,  in  which  a 
small  bubble  of  gas  that  has  been  drawn  into  a  capillary  tube 
is  analyzed,  has  been  brought  to  a  high  grade  of  efficiency 
through  the  efforts  of  Barcroft  and  Hamill,  Brodie  and  Cul- 
lis,  and  of  Krogh.39 

Cohnheim's  Respiration  Apparatus  for  Isolated  Organs. 
— Otto  Cohnheim,  moreover,  has  introduced  a  respiration  ap- 
paratus for  isolated  organs  constructed  on  the  principle  of 
the  respiration  apparatus  of  Atwater  and  Benedict.  A  given 
amount  of  oxygen  is  circulated  in  a  closed  system ;  due  to  the 
oxygen  consumption  by  the  organ  the  volume  of  the  oxygen  is 
lowered,  and  this  diminution  is  determined  by  a  manometer ; 
and  finally  from  a  small  bomb  enough  oxygen  is  allowed  to 
enter  to  bring  the  manometer  back  to  its  original  register. 
The  loss  in  weight  of  the  bomb  gives  the  amount  of  oxygen 
consumed;  the  carbonic  acid  is  weighed  after  absorption 
in  moist  soda  lime.  Many  isolated  organs  may  be  studied 
immersed  in  Ringer's  solution;  in  other  cases  the  oxygen 

s»Cf.  T.  G.  Brodie,  Jour,  of  Physiol.,  39,  391,  1910. 


574  TISSUE  RESPIRATION 

is  introduced  directly  by  way  of  the  blood  vessels  of  the 
organ  which  may  remain  in  situ.40 

Thunberg's  Microrespirometer. — If,  finally,  there  be 
occasion  to  study  the  respiration  of  very  small  organs, 
Thunberg's  microrespirometer  will  serve  the  purpose  fairly 
well.  The  apparatus  consists  of  two  small  flasks  which  are 
joined  hermetically  by  a  horizontal  capillary  tube.  A  drop- 
let of  oil  within  this  capillary  tube  moves  toward  the  side  of 
lower  pressure.  An  organ  is  placed  in  one  of  the  flasks; 
when  if  the  respiration  quotient 41  is  greater  than  1,  that  is 
if  more  carbonic  acid  be  produced  than  the  amount  of 
oxygen  consumed,  the  indicator  drop  moves  away  from  the 
organ,  but  in  the  reverse  case  toward  the  organ.  If  a  small 
amount  of  potassium  hydrate,  however,  be  placed  at  the 
bottom  of  the  vessel  the  carbonic  acid  is  absorbed  and  the 
movement  of  the  droplet  directly  expresses  the  intake  of 
oxygen. 

By  methods  of  this  sort  the  individual  organs  have  been 
tested  under  the  most  varied  physiological  conditions.  The 
detailed  results  of  study  may  be  passed  over  and  only  the 
most  important  points  in  question  involved  may  be  here 
indicated  with  all  brevity.  The  answers  to  these  are  at  best 
for  the  most  part  rather  contradictory.42 

Gas  Interchange  of  Muscle. — In  case  of  the  skeletal 
muscles  the  relations  between  their  functional  efficiency  and 
gas  exchange  have  been  the  subject  of  a  large  number  of 
investigations,  particularly  at  the  hands  of  C.  Ludwig, 
v.  Frey,  Chauveau  and  Kaufmann,  Zuntz  and  Thunberg. 
The  last  named  author  found  by  the  aid  of  his  microrespi- 
rometer that  the  intake  of  oxygen  by  a  frog's  muscle  is  in  a 
general  way  a  measure  of  the  irritability  of  the  muscle,  but 

40  Otto  Cohnheim,  VIII  internat.  Physiol.  Kongr.  Vienna,  Sept.,  1910; 
Zeitschr.  f.  physiol.  Chem.,  69,  89,  1910. 

41  The  respiratory  quotient,  however,  may  be  falsified  in  these  experiments 
by  the  fact  that  lactic  acid  of  post  mortem  development  displaces  carbonic  acid 
from  any  carbonates  which  are  present. 

42 Literature:    J.  Barcroft,  Ergebn.  d.  Physiol.,  7,  699-762,  1908. 


OXYGEN  REQUIREMENT  OF  NERVOUS  TISSUE    575 

that  a  muscle  rendered  incapable  of  excitation  by  some 
poison  continues  to  show  a  not  inconsiderable  capacity  for 
taking  up  oxygen.  According  to  Verzär  the  quantity  of 
acid  entering  into  the  blood  in  connection  with  muscular 
contraction  is  sufficient  to  reduce  the  affinity  of  the  haemo- 
globin for  oxygen.  The  fact  that  for  a  considerable  time 
after  the  expiration  of  a  contraction  muscle  shows  an  in- 
crease in  its  oxygen  consumption  is  significant  of  the  im- 
portance of  oxygen  in  the  process  of  its  recovery.43  System- 
atic studies  of  the  gas  interchange  of  the  smooth  muscle 
of  the  stomach  and  intestine  have  been  made  by  0.  Cohn- 
heim  by  his  method.44 

Numerous  studies  have  been  made  of  the  gas  exchange 
of  the  heart.  They  are  largely  devoted  to  comparison  of 
the  cardiac  muscle  with  the  skeletal  muscles,  the  relation 
of  gas  interchange  with  the  rhythm  and  mechanical  actions, 
the  influence  of  vagus  stimulation  and  of  various  poisons 
(as  calcium  chloride,  chloroform,  alcohol,  digitalin,  adren- 
in,  etc.).  The  method  of  perfusing  the  surviving  heart  of  a 
warm-blooded  animal  with  blood  which  Eohde  has  carefully 
worked  out  in  R.  Gottlieb's  laboratory  promises  important 
results  in  combination  with  the  modern  methods  of  blood 
gas  analysis.45 

Oxygen  Requirement  of  Nervous  Tissue. — The  respira- 
tory processes  of  the  nervous  system  have  been  studied 
particularly  by  Hill  and  Nabarro,  F.  W.  Frölich46  (in  Ver- 
worn's  laboratory)  and  by  H.  Winterstein.47  Frölich  be- 
lieves that  on  augmentation  of  their  oxygen  allowance  the 
excitability  of  nerves  is  increased  up  to  a  certain  degree, 

«F.  Verzär  (Physiol.  Lab.,  Cambridge),  Jour,  of  Physiol.,  U,  253,  1912; 
cf.  also  G.  C.  Mathison,  Jour,  of  Physiol.,  W,  347,  1911. 

44  0.  Cohnheim,  Zeitschr.  f.  physiol.  Chem,  5-J,  461,  1908;  0.  Cohnheim  and 
D.  Pletnew,  Zeitschr.  f.  physiol.  Chem.,  69,  102,  1910. 

45  Yeo,  W.  E.  Dixon  (Cambridge),  Brodie  and  Cullis,  Locke  and  Rosen- 
heim, G.  D.  Cristina  (Naples),  Arch.  di.  Fisiol.,  5,  347,  1908;  E.  Rohde  (R. 
Gottlieb's  Lab.,  Heidelberg),  Arch.  f.  exper.  Pathol.,  68,  401,  1912. 

49  F.  W.  Frölich  (Verworn's  Lab.,  Göttingen),  Zeitschr.  f.  allgem.  Physiol., 
3,  131,  1903. 

47  H.  Winterstein  (Rostock),  Zeitschr.  f.  allgem.  Physiol.,  6,  315,  1906. 


576  TISSUE  RESPIRATION 

and  that  beyond  this  limit  all  the  oxygen  taken  up  by 
nervous  substance  is  accumulated  as  an  oxygen  store.  On 
the  other  hand  Winterstein  showed  in  case  of  the  isolated 
frog's  spinal  cord  that  after  asphyxiating  his  preparation 
in  an  atmosphere  of  nitrogen  there  was  no  more  oxygen 
taken  up  at  time  of  recovery  than  in  ordinary  respiration. 
He  concluded  from  this  that  oxygen  storage  does  not  take 
place  in  the  living  body,  and  that  asphyxiation  is  not  the 
result  of  exhausting  the  oxygen  store  but  is  due  rather  to 
accumulation  of  anaerobic  cleavage-products  apparently  of 
an  acid  character;  of  course  lactic  acid  is  to  be  thought 
of  at  once. 

Gas  Interchange  of  the  Salivary  Glands. — The  gas  ex- 
change of  the  salivary  glands  has  been  thoroughly  inves- 
tigated by  Barcroft,  at  the  suggestion  of  Langley  (in  se- 
quence to  the  older  studies  of  Chauveau  and  Kaufmann  and 
of  Moussu  and  Tissot).  Stimulation  of  the  chorda  undoubt- 
edly increases  the  gas  exchange  of  the  submaxillary  gland ; 
the  influence  of  sympathetic  stimulation  is  more  difficult  to 
determine,  as  the  effect  is  masked  by  a  reduction  of  the 
blood  flow.  Barcroft  believes,  however,  that  the  sympa- 
thetic is  not  directly  inhibitive  to  metabolism  in  the  gland. 
He  showed  (in  collaboration  with  Piper)  that  injection  of 
adrenin  calls  forth  a  very  much  increased  demand  for 
oxygen  in  the  gland,  apparently  occasioned  by  stimulation 
of  the  sympathetic.  There  first  was  a  rise  in  blood  pres- 
sure after  the  injection,  then  an  increase  in  the  secretion 
of  saliva;  the  increase  in  oxygen  consumption,  however, 
reached  its  maximum  after  the  salivary  secretion  was  almost 
finished.  The  conclusion  from  this  is  that  it  is  not  the  secre- 
tion itself  but  the  recovery  and  the  restoration  of  secretory 
material  which  calls  out  the  main  expenditure  of  energy.48 

Gas  Exchange  in  the  Liver  and  Kidney. — In  case  of 
hepatic  gas  exchange  it  is  apparently  proved  that  it  is  more 

48  J.  Barcroft,  1.  c.  p.  731-741;  J.  Barcroft  and  H.  Piper,  Jour,  of  Physiol., 
U,  359,  1912. 


ANOXYBIOTIC  PROCESSES  577 

active  in  well  fed  animals  than  in  fasting  subjects  from 
the  studies  of  Barcroft  and  Shore.49  In  the  kidney  the  in- 
terchange of  gases  is  undoubtedly  increased  in  the  course 
of  an  experimentally  induced  diuresis  (as  indicated  by 
investigations  of  Barcroft,  Brodie,  Cullis  and  Hamill).  One 
may  strikingly  maintain,  according  to  Vernon,  the  gas  in- 
terchange at  a  fairly  constant  level  for  many  hours  by  per- 
fusing a  fresh  mammalian  kidney  with  Locke's  solution  to 
which  have  been  added  a  little  blood-serum  and  urea.50 

Gas  Exchange  of  the  Intestine. — Finally  it  should  be 
added  that  the  gas  exchange  of  the  intestine  has  been  in- 
vestigated by  v.  Frey,  Cohnheim  and  by  Brodie  51  (in  asso- 
ciation with  Halliburton,  Vogt  and  Cullis),  and  that  the 
results  would  indicate  that-  whenever  there  is  an  increase 
of  absorption  (whether  induced  by  contact  of  water,  dilute 
salt  solutions,  peptone  or  dilute  acids)  a  rise  in  the  gas 
exchange  ensues. 

The  examples  cited  are  sufficient  to  show  the  lines  along 
which  these  studies  tend.  The  most  important  general  re- 
sult that  stands  out  is  the  fact  that  practically  always 
increased  functional  performance  by  an  organ  is  accom- 
panied by  an  increase  in  its  gas  interchange. 

Anoxybiotic  Processes. — These  considerations  of  tissue 
respiration  may  be  concluded  with  a  short  reference  to 
anoxybiotic  processes. 

Bunge  in  1883  called  attention  to  the  remarkable  fact 
that  there  are  animals  which  are  capable  of  living  in  the 
absence  of  oxygen.  These  are  the  intestinal  worms,  para- 
sitic in  the  warm-blooded  animals,  forms  of  life  whose  needs 
for  heat-production  are  necessarily  reduced  to  a  minimum, 
as  they  normally  inhabit  a  living  incubator.  Mud-dwelling 
forms  live  under  comparable  respiratory  conditions  to  those 

49  J.  Barcroft  and  L.  E.  Shore  (Physiol.  Lab.,  Cambridge),  Jour,  of 
Physiol.,  If5,  296,  1912. 

60  H.  M.  Vernon  (Oxford),  Jour,  of  Physiol.,  35,  53,  1906;  36,  81,  1907-08. 

61  Brodie,  in  collaboration  with  W.  C.  Cullis,  W.  D.  Halliburton  and  H. 
Vogt,  Centralbl.  f.  Physiol.,  23,  324,  1909;  Jour,  of  Physiol.,  Jt0,  136,  173,  1910. 

37 


578  TISSUE  RESPIRATION 

of  the  intestinal  worms.  Bunge  's  studies  were  made  upon  the 
ascarides  of  the  cat,  horse  and  pig  and,  too,  upon  leeches. 
He  found  that  the  former  can  exist  for  from  four  to  six 
days  outside  the  body  in  a  practically  oxygen-free  fluid, 
manifesting  very  active  movements,  and,  obviously  as  the 
result  of  cleavage  processes  in  their  tissues,  giving  off 
abundant  amounts  of  carbonic  acid.  These  studies  by 
Bunge  were  later  continued  by  Ernst  Weinland  in  Munich. 
The  latter  was  at  once  struck  by  the  large  amount  of  gly- 
cogen contained  in  the  intestinal  parasites ;  the  dried  sub- 
stance of  an  ascaris  may  consist  of  as  much  as  one-third 
and  that  of  a  taenia  of  as  much  as  one-half  of  glycogen. 
Obviously  the  anoxybiotic  decomposition  of  this  carbohy- 
drate, a  form  of  fermentation  process,  is  the  most  impor- 
tant source  of  energy  from  which  these  types  of  life  pro- 
vide their  requirements.  According  to  Weinland  the  sugar 
is  decomposed  in  them  into  carbonic  acid,  valerianic  acid  and 
hydrogen,  according  to  the  following  equation:  4C6H1206  = 
9C02  +  3C5H10O2  +  9H2  (although  it  should  be  added  the 
formation  of  hydrogen  has  not  been  directly  proven).  Ernst 
J.  Lesser  has  discovered  that  a  marked  anoxybiotic  glycogen 
decomposition  may  also  be  observed  in  earthworms,  which 
may  amount  to  six  times  the  rate  of  oxybiotic  glycogen  de- 
composition, and  in  which  in  addition  to  carbonic  acid  a 
volatile  fatty  acid,  apparently  valerianic  acid,  appears. 
Methane,  hydrogen  and  alcohol  are  apparently  not  present. 
The  previously  presented  efforts  seeking  to  establish  an 
alcoholic  fermentation  as  a  normal  process  of  intermediate 
metabolism  in  the  animal  economy,  therefore  receive  no 
support,  at  least  from  these  investigations.52 

e2 Literature  upon  Anoxybiotic  Vital  Processes  in  Animals:   O.  v.  Fürth, 
Vergl.  chem.  Physiol,  der  niederen  Tiere,  pp.  134-136,  Jena,  1903;    E.  J.  Lesser, 
Zeitschr.  f.  Biol.,  52,  282;  53,  533;  5k,  1;  56,  467,  1911;  Ergebn.  d.  Physiol. 
8,  786-796,  1909. 


CHAPTER  XXIV 

THE  COLORING  MATTER  OF  THE  BLOOD.  THE  GASES 
OF  THE  BLOOD.  GAS  INTERCHANGE  IN  THE  LUNGS. 
PHYSIOLOGY  OF  ALPINISM 

HiEMOGLOBIN 

The  processes  of  tissue  respiration  naturally  predicate 
the  existence  of  arrangements  which  make  possible  intro- 
duction of  oxygen  and  elimination  of  the  carbonic  acid 
formed  in  the  combustion  changes.  These  provisions  in  the 
warm-blooded  animals  are,  as  is  well  known,  provided  by 
the  red  coloring  matter  of  the  blood.  In  a  previous  lecture 
(v.  Vol.  I  of  this  series,  pp.  211-227,  Chemistry  of  the  Tis- 
sues) consideration  has  been  given  to  the  component  haenia- 
tin,  and  its  derivatives;  attention  may  therefore  here  be 
devoted,  from  a  physiological  standpoint,  to  haemoglobin  as 
a  whole.1 

Production  of  Hämoglobin  Crystals. — Haemoglobin,  it  is 
well  known,  belongs  to  the  group  of  crystallizable  proteins. 
In  many  readily  crystallizable  types  of  blood  one  may 
obtain  beautiful  haemoglobin  crystals  by  the  simple  method 
of  Hoppe-Seyler,  by  laking  the  blood  and  placing  it  in  a 
cold  place  (perhaps  with  addition  of  a  little  alcohol).  Fol- 
lowing the  Hofmeister  method  of  albumin  crystallization, 
F.  N.  Schulz  obtained  beautifully  formed  crystals  of  haemo- 
globin by  taking  a  mass  of  red  blood  cells,  making  a  laked 
solution  with  water,  and  then  adding  an  equal  volume  of 
saturated  solution  of  ammonium  sulphate.  The  precipitate 
of  globulin-like  substances  is  then  filtered  off  and  the  filtrate 
allowed  to  stand.  By  the  process  of  salting  out  resulting 
from  the  gradual  evaporation  the  haemoglobin  separates  in 
the  form  of  crystals. 

Variability  of  Hämoglobin. — The  crystals  obtained  from 

1  Literature  upon  Haemoglobin:  Franz  Müller,  Handb.  d.  Biochem.,  1,  662- 
666,  670-678,  1909;  0.  Cohnheim,  Chemie  der  Eiweisskörper,  3rd  Ed.,  1911. 

579 


580  THE  COLORING  MATTER  OF  BLOOD 

the  blood  of  different  animal  species  vary  considerably.  As 
a  rule  they  form  needles,  prisms  and  plates  of  rhombic 
system ;  the  hexagonal  crystals  of  the  squirrel  and  the  tetra- 
hedra  of  guinea-pig  haemoglobin  are  well  known.  Formerly 
much  importance  was  made  of  such  differences.  It  has  been 
shown,  however,  that  by  repeated  recrystallization  one  form 
of  crystal  can  be  converted  into  another ; 2  that  therefore 
we  are  dealing  with  a  typical  heteromorphism  which  may 
be  looked  upon  as  an  expression  of  a  certain  molecular 
instability.  When  we  take  up  the  question  of  the  chemical 
identity  of  haemoglobin,  however,  there  are  a  number  of 
other  factors  to  be  taken  into  consideration.  In  the  first 
place  it  should  be  remembered  that  even  by  repeated  re- 
crystallization  it  is  not  always  possible  to  exclude  with 
certainty  the  admixture  of  other  high  molecular  substances. 
Besides  it  is  an  important  point  (confirmed  particularly  by 
the  studies  of  Barcroft  and  his  collaborators)  to  remember 
that  the  dissociation  of  oxyhemoglobin  into  haemoglobin 
and  oxygen  is  subject  to  an  influence  from  the  salts  and 
the  carbonic  acid  in  the  surrounding  medium  and  of  course, 
too,  from  numerous  other  factors.3  We  know,  moreover, 
that  haemoglobin  is  an  extremely  labile  substance,  the  pro- 
tein component  of  which  may  undergo  distinct  changes  even 
from  being  left  exposed  and  from  drying  (Nencki's  "  para- 
hcemoglobin")  without  this  being  necessarily  evinced  by 
any  important  change  of  form  or  even  any  loss  of  refractive 
power.  And,  finally,  attention  has  been  directed  by  the 
investigations  of  H.  Aron  and  Franz  Müller 4  to  the  point 
that  differences  between  the  behavior  of  blood  solutions 
and  pure  haemoglobin  solutions  may  be  caused  by  partial 
conversion  of  oxyhemoglobin  into  methsemoglobin  (vide 
infra),  this  being  at  times  indeed  met  even  in  normal  blood. 

2M.  Uhlik  (Innsbruck),  Pflüger's  Arch.,  10k,  64,  1904. 

s Barcroft  and  M.  Camis  (Physiol.  Instit.,  Cambridge),  Jour,  of  Physiol., 
39,  118,  1909. 

4H.  Aron  (N.  Zuntz's  Lab.),  Biochem.  Zeit3chr.,  3,  1,  1906;  H.  Aron  and 
F.  Müller  (N.  Zuntz's  Lab.),  Arch.  f.  (Anat.  u.)  Physiol.,  1906;  suppl.  110. 


INDIVIDUALITY  OF  HEMOGLOBIN  581 

Hcemochrome  and  Crystallized  Blood  Coloring  Matter. — 
When  these  points  are  kept  in  mind  there  is  no  need  to  be 
surprised  that  the  observations  made  in  reference  to  the 
red-blood  coloring  matter  are  not  of  a  uniformly  consistent 
nature.  After  Bohr  had  brought  forward  the  real  blood 
coloring  matter,  ' '  haeniochrome, ' '  in  contrast  to  the  crystal- 
lized coloring  material  obtained  from  the  blood,  the  cor- 
rectness of  this  counterview  became  the  subject  of  warm 
discussion. 

Thus  Franz  Müller  assumed  with  Bohr  "that  the  color- 
ing matter  of  different  individuals  of  the  same  species  and 
of  the  same  individual  at  different  times  may  have  differ- 
ent light  absorption  properties  and  a  varying  proportion 
of  iron,  and  that  these  variations  are  particularly  appreci- 
able in  conditions  of  blood  regeneration  and  in  pathological 
states."  However  even  in  the  crystals  produced  from  the 
native  coloring  material  it  would  seem  that  the  specific 
capacity  for  oxygen  may  be  as  individualized  as  in  case  of 
the  blood  coloring  matter  itself  and  may  vary  among  differ- 
ent animal  species.5 

Individuality  of  Hccmoglobin. — In  contradiction  to  this 
position,  however,  it  must  be  stated  that  studies  by  Abder- 
halden on  goose-blood,6  similar  observations  in  v.  Zeynek's 
laboratory  on  the  blood  of  sea  turtles,7  and  studies  in  the 
Heidelberg  medical  clinic 8  of  the  blood  of  healthy  and  dis- 
eased human  beings,  bespeak  throughout  the  individuality 
of  pure  haemoglobin.  Above  all,  however,  the  many  studies, 
carried  out  with  the  utmost  precision  by  the  recently-de- 
ceased master  of  haemoglobin  research,  G.  Hiifner,  and  the 


6F.  Müller,  Handb.  d.  Biocbem.,  1,  669,  675,  1909;  cf.  also  A.  Bornstein 
and  F.  Müller,  Physiol.  Kongress,  Heidelberg,  1907,  Centralbl.  f.  Physiol,  21, 
478,  1907. 

6  E.  Abderhalden  and  F.  Medigreceanu,  Zeitschr.  f.  physiol.  Chem.,  59,  165, 
1909. 

7  F.  Bardachzi  (v.  Zeynek's  Lab.,  Prague),  Zeitschr.  f.  physiol.  Chem., 
49,  465,  1906. 

8E.  Masing  (Med.  Clinic  of  Krehl,  Heidelberg),  Deutsch.  Arch.  f.  klin. 
Med.,  98,  122,  1909;  E.  Masing  and  R.  Siebeck,  ibid.,  99,  130,  1910. 


582  THE  COLORING  MATTER  OF  BLOOD 

extensive  work  of  his  pupil,  Butterfield,9  emphasize  the  view 
that  in  iron  proportions,  ability  to  combine  oxygen,  and  in 
spectrophotometry  of  pure,  unchanged  red  blood  coloring 
matter  in  all  the  instances  of  normal  and  diseased  human 
beings  and  animals  examined,  there  is  no  variation.  Of 
course  it  has  not  been  proved  and  (according  to  everything 
immunology  and  precipitin  study  indicate)  is  not  even  prob- 
able that  the  colorless  protein  components  of  all  haemo- 
globins of  the  general  animal  kingdom  are  actually  identical 
among  themselves.  The  molecular  weight  of  haemoglobin 
has  been  estimated  by  Hüfner  as  about  16,000  (from  the 
iron  contained,  its  capacity  for  C02  fixation  and  from  direct 
manometric  measurements  of  the  osmotic  pressure  of  its 
solution  if  placed  in  a  semipermeable  cell).10  Who  would 
care  to  undertake  to  prove  that  two  substances  with  such  a 
molecular  weight  are  identical!  But  we  have  no  reason  to 
assume  that  the  differences  between  different  haemoglobins 
(as  far  as  they  exist)  manifest  themselves  by  a  difference  in 
their  iron  content  and  their  power  of  taking  up  oxygen.  The 
observations  bearing  on  these  points,  in  the  author's  opinion, 
are  satisfactorily  explained  by  the  previously-mentioned  ac- 
cessory factors  and  by  the  secondary  processes  of  decomposi- 
tion; and  we  doubtless  would  do  well  not  to  unnecessarily 
make  it  harder  than  necessary  to  comprehend  the  already 
complicated  circumstance  of  oxygen  fixation  in  the  blood  by 
assuming  that  there  is  an  unlimited  multiplicity  of  haemo- 
globins. As  0.  Cohnheim  1X  cautions,  since  chemists  who 
are  disposed  to  study  the  physical-chemical  balance  between 
haemoglobin  and  oxygen,  work  with  pure  and  unchanged 
haemoglobin,  while  the  physiologists,  who  have  to  do  with 
the  question  of  oxygen-transportation  in  the  economy,  carry 
on  their  researches  with  blood  as  little  changed  as  possible, 

•  E.  E.  Butterfield,  Zeitschr.  f .  physiol.  Chem.,  62,  173,  1909. 

10  G.  Hüfner  and  E.  Gansser,  Arch.  f.  (Anat.  u.)  Physiol.,  1901,  209; 
E.  W.  Reid  (Dundee),  Jour.  of.  Physiol.,  33,  12,  1905-06;  J.  Barcroft  and 
J.  V.  Hill,  ibid.,  39,  428,  1909-10. 

n  O.  Cohnheim,  1.  c.,  p.  359. 


METHAEMOGLOBIN  583 

it  may  easily  be  seen  how  contradictory  results  may  enter 
into  the  subject  at  once. 

Importance  of  the  Iron  in  the  Blood  Coloring  Matter. — 
Before  going  further  the  question  of  the  importance  of  the 
iron  in  the  coloring  matter  of  the  blood  may  be  briefly  dis- 
cussed. In  a  previous  lecture  (v.  Vol.  I  of  this  series,  p.  213, 
Chemistry  of  the  Tissues)  it  was  stated  that  according  to 
William  Küster 's  investigations  iron  is  present  both  in 
haemin  and  in  haematin  in  the  ferric  state ;  the  f erri  chloride 
group,  FeCl=,  in  haeinin  and  the  ferri  hydroxide  group, 
FeOH=,  in  haematin  replacing  the  hydrogen  atom  in  the 
imido  group  of  pyrrol  complexes.  The  ferri  compound, 
haematin,  can  be  reduced  to  the  ferro  compound,  haemo- 
chromogen.  It  seems,  however,  that  haematin  is  not  a  com- 
ponent of  oxyhemoglobin,  but  of  methaemoglobin,  which  has 
all  the  characters  of  a  ferri  compound.  According  to  Küster 
the  following  connections  exist : 

Haemoglobin  —  Globin  -f-  Haemochromogen  K>Fe 
Oxyhaemoglobin  =  Globin  -j-  Haemochromogen  peroxide 

E>Fe....02 
Methaemoglobin  =  Grlobin  -f  Haematin  R>Fe  —  OH ; 

and  he  is  unable  to  recognize  any  force  in  Manchot's  argu- 
ments that  haemoglobin  is  a  ferri  compound.12 

Methcemo  globin. — According  to  this  view,  the  iron  of 
methaemoglobin  13  is  trivalent  ferric  iron,  which  is  no  longer 
able  to  loosely  fix  oxygen  and  is  much  more  stable  than 
oxyhaemoglobin.  The  latter  has  a  tendency  to  become  met- 
haemoglobin, and  even  in  the  living  blood  it  is  well  known 
that  a  number  of  poisons  are  able  to  induce  this  transition. 
By  a  reducing  agent  (as  ammonium  sulphide  or  Stokes' 
reagent)  methaemoglobin  can  be  reconverted  into  haemoglo- 
bin.   Hüfner  succeeded,  it  may  be  mentioned  in  passing,  in 

12  W.  Küster,  Zeitschr.  f.  physiol.  Chem.,  66,  248,  1910;  11,  104,  1911; 
W.  Manchot  (Würzburg),  ibid.,  10,  230,  1910. 

13  Literature  upon  Methaemoglobin:    0.  Cohnheim,  1.  c.,  345-349. 


584  THE  GASES  OF  THE  BLOOD 

obtaining  methaemoglobin  in  crystalline  form  (its  acid  solu- 
tion produces  a  brown  color).  A  fluorine  combination  of 
methaemoglobin  may  also  be  obtained  in  crystalline  state, 
by  mixing  a  solution  of  methaemoglobin  with  concentrated 
solution  of  sodium  fluoride-ammonium  sulphate,  and  chilling 

to  0°  C.14 

BLOOD  GASES 

Technic  of  Blood  Gas  Analysis. — The  technic  of  blood 
gas  analysis  belongs  among  the  most  difficult  and  yet  the 
most  carefully  worked  out  chapters  of  physiological  technol- 
ogy. To  some  extent  it  has  been  dealt  with  in  the  previous 
lecture;  but  here,  too,  reference  must  be  limited  to  a  few 
brief  statements,  and  the  various  handbooks  must  be  con- 
sulted for  details.15 

As  the  union  between  haemoglobin  and  oxygen  is  broken 
in  a  vacuum,  it  is  possible  to  withdraw  the  latter  from  the 
blood  by  means  of  an  air-pump.  The  distinguished  role 
accorded  Pflüger  's  blood-gas  pump  in  the  history  of  physi- 
ology is  a  matter  of  common  knowledge.  More  modern  ap- 
paratuses of  this  kind  have  been  proposed  by  Zuntz,  Bohr, 
and  by  Buckmaster  and  Gardner.16  More  recently  the  pump 
methods  have  given  way  more  and  more  to  the  chemical 
method  of  blood-gas  analysis,  which  is  not  only  much  more 
satisfactory  and  simpler,  but  has  in  addition  the  great  ad- 
vantage of  being  adapted  to  the  employment  of  very  small 
quantities  of  blood.  As  already  stated,  the  oxygen  is  set 
free  from  the  blood  by  potassium  ferricyanide,  and  the 
method,  perfected  by  Haldane,  Barcroft,  Brodie,  Hamill 
and  Franz  Müller,  works  with  a  remarkably  high  degree 
of  exactness. 

The  tension  of  the  gases  in  the  blood  may  be  determined 

14  J.  Ville  and  Derrien,  Compt.  rendu,  U0,  1195,  1905. 

15  Literature  upon  the  Methods  of  Blood  Gas  Analysis :  A.  Löwy,  Handb. 
d.  Biochem.,  4'>  17-24,  1908;  Franz  Müller,  Handb.  d.  biochem.  Arbeitsmethod., 
S,  555,  1910;  5,  1027-1034,  1912;  Bohr,  Tigerstedt's  Handb.  d.  physiol. 
Methodik,  2,  1,  1910;  J.  Barcroft  and  P.  Morawitz  (Physiol.  Instit.,  Cam- 
bridge), Deutsch.  Arch.  f.  klin.  Med.,  93,  223,  1908. 

16  G.  A.  Buckmaster  and  J.  A.  Gardner,  Jour,  of  Physiol.,  JfO,  373,  1910. 


TECHNIC  OF  BLOOD  GAS  ANALYSIS  585 

by  means  of  blood  gastonometers  17  as  used  by  Pflüger,  Fred- 
ericq,  Bohr,  Krogh  and  Löwy.  They  all  depend  on  the  prin- 
ciple that  blood  is  brought  in  contact  with  a  mixture  of 
gases  until  a  complete  tension  balance  is  attained  and  the 
partial  pressure  of  the  gases  is  then  determined.  The 
balance  is  quickly  obtained  if  the  volume  of  gas  is  reduced 
to  a  minimum  as  in  a  microtonometer. 

In  the  method  of  Haldane  and  Lorraine  Smith  the  oxygen 
is  determined  in  a  specimen  of  blood  by  means  of  ferri- 
cyanide;  in  another  specimen  the  oxygen  is  forced  out  by 
carbon  monoxide  and  the  color  of  the  carbon  oxide  blood 
compared  with  a  carmine  solution  of  known  proportions. 
Plesch  has  proposed  a  wedge  hsemoglobinometer ;  the  blood 
to  be  tested,  diluted  200  times,  is  converted  into  carbon- 
oxide  blood  by  shaking  it  up  with  illuminating  gas  and  this 
compared  with  a  standard  fluid  (blood  with  known  propor- 
tion of  carbon  oxide).  The  apparatus  consists  of  two  gradu- 
ated tubes,  one  of  which  receives  the  blood  to  be  tested,  the 
other  the  standard  fluid.  In  the  latter  is  a  wedge  arranged 
so  that  the  visual  thickness  diminishes  from  below  upwards. 
The  result  is  read  off  by  observing  the  tubes  through  a 
small  aperture  and  moving  one  tube  until  the  colors  coin- 
cide. In  a  method  devised  by  Zuntz  and  Plesch,  which  has 
been  found  applicable  to  the  study  of  circulating  blood  in 
the  living  animal,  the  carbon  oxide  is  forced  out  of  the  blood 
by  potassium  ferricyanide,  oxidized  into  carbonic  acid  by 
passing  over  glowing  platinum,  the  carbonic  acid  absorbed 
by  potassium  hydrate  and  the  carbon  oxide  determined  by 
Barcroft-Haldane  method  from  the  observed  change  of  pres- 
sure. Dreser  has  also  devised  a  method  for  determining 
the  carbon  oxide  combined  in  small  quantities  of  blood;  in 
which  he  uses  a  small  mercury  pump,  measuring  the  amount 
of  gas  obtained  in  a  capillary  tube. 

The  new  nitrous  oxide  method  devised  by  Zuntz  in  col- 
laboration with  MarkofT  and  Franz  Müller  provides  a  very 

17  Cf.  Literature  in  Ch.  Bohr,  Skandin.  Arch.  f.  Physiol.,  17,  205,  1905. 


586  THE  GASES  OF  THE  BLOOD 

satisfactory  mode,  applicable  also  to  estimation  of  the  cir- 
culating blood  in  the  living  human  body.  The  subject  in- 
spires from  a  gasometer  which  contains  a  gas  mixture  of 
known  composition  rich  in  nitrous  oxide  but  providing  suffi- 
cient oxygen.  The  amount  of  nitrous  oxide  taken  up  by  the 
blood  during  respiration  is  determined  by  analysis.  On  the 
basis  of  the  determinations  of  Siebeck  as  to  the  intake  of 
nitrous  oxide  by  blood  it  can  then  easily  be  determined 
how  much  blood  must  have  passed  through  the  lungs  to 
have  taken  up  at  the  given  partial  pressure  the  amount 
removed  from  the  mixture.18 

Objective  Hcemoglobinometry  and  Spectrophotometry. — 
Attention  should  be  paid  to  two  recent  methods  of  interest- 
ing device.  In  each  the  purpose  attempted  is  an  objective 
hagmoglobinometry  intended  to  make  the  observer  independ- 
ent of  the  question  of  keenness  of  his  subjective  sense- 
perceptions.  This  is  accomplished  by  J.  Plesch  by  replacing 
the  eye  of  the  observer  in  comparing  the  concentrations  of 
color  solutions  by  a  selenite  cell  traversed  by  an  electric 
current.  It  is  well  known  that  selenium  possesses  the  prop- 
erty of  changing  its  electrical  conductivity  under  the  in- 
fluences of  light,  apparently  owing  to  a  polymerization  due 
to  the  light.  By  having  the  light  coming  from  a  fixed  source 
traverse  a  trough  filled  with  the  color  solution  before  falling 
upon  the  selenium  cell,  the  variation  in  current  resistance, 
which  may  be  measured  by  a  sensitive  galvanometer,  is 
made  to  serve  as  an  objective  index  of  the  degree  of  light 
absorption.19 

The  other  method  referred  to  is  a  photographic  record 
of  intensity  dispersion  in  blood  spectra  recently  perfected 
by  Wolfgang  Heubner.20  The  method  of  spectrophotometric 

w  J.  Markoff,  Franz  Müller  and  N.  Zuntz,  Zeitschr.  f .  Balneol.,  4>  Nos.  14- 
15,  1911-12. 

M  J.  Plesch  (N.  Zuntz's  Lab.),  Biochem.  Zeitschr.,  1,  32,  1906. 

20  W.  Heubner  (Göttingen),  VIII  Intern.  Physiologen-Kongr.,  Wien.,  Sept., 
1910;  Deutsche  med.  Wochenschr.,  1911,  No.  11;  W.  Heubner  and  H.  Rosenberg, 
Biochem.  Zeitschr.,  3S,  345,  1911. 


OXYGEN  FIXATION  IN  BLOOD  587 

measurement  in  special  application  to  haemoglobin  and  its 
derivatives  has  been  brilliantly  developed  by  G.  Hiifner.21 
"The  direction  of  prospective  improvement  of  method," 
says  Hiifner,  "was  indicated  beforehand  in  the  recording 
of  the  spectral  image  photographically,  so  often  done  previ- 
ously with  good  results.  The  method  is  particularly  ad- 
vantageous because  the  long-drawn  photometric  observa- 
tion can  be  interrupted  for  the  quickly  accomplished  record- 
ing on  the  spot  of  the  general  spectral  field,  allowing,  for 
example,  rapid  chemical  reactions  which  occur  with  a  change 
of  light  absorption  to  be  followed  with  ease  and  exactness. ' ' 
It  is  a  matter  of  interest  that  the  fundamental  studies  which 
have  led  to  the  development  of  the  photographic-photometric 
method,  have  been  applied  by  an  astronomer  (K.  Schwarz- 
schild) to  the  study  of  the  stars — a  fine  example  of  organic 
exchange  between  two  widely  separated,  flourishing  branches 
of  the  tree  of  modern  science. 

Coefficients  of  Absorption,  Invasion  and  Evasion. — Con- 
sideration of  oxygen  fixation  in  the  blood  must  necessarily 
be  based  upon  the  general  laws  of  solution  of  gases  in  fluids. 
We  have  therefore  to  deal  with  the  coefficients  of  absorption, 
invasion  and  evasion.  The  absorption  coefficient  is  that 
amount  of  gas  which  is  contained  in  one  cubic  centimetre 
of  a  fluid  saturated  with  gas  at  0°  C.  and  at  760  mm.  pres- 
sure. That  quantity  of  gas  which  at  given  temperature 
and  760  mm.  pressure  will  penetrate  into  the  fluid  in  the 
course  of  one  minute  through  a  surface  of  one  square  centi- 
metre is  known  as  the  invasion  coefficient.  That  quantity 
of  gas  which  will  escape  in  one  minute  from  a  surface  of 
one  square  centimetre,  providing  one  cubic  centimetre  of 
the  fluid  contains  one  cubic  centimetre  of  gas,  is  spoken  of 
as  its  evasion  coefficient. 

Oxygen  is  absorbed  in  the  plasma,  but  is  peculiarly  com- 

31  Literature  upon  Spectrophotometry  of  the  Hämoglobins :  Biircker,  Tiger- 
stedt's  Handb.  d.  physiol.  Methodik,  2',  68,  1910. 


588  THE  GASES  OF  THE  BLOOD 

bined  in  the  haemoglobin  of  the  blood.  The  solvent  capacity 
of  the  plasma  for  oxygen  does  not  appreciably  differ  from 
that  of  water.  In  spite  of  the  fact  that  the  plasma  there- 
fore contains  relatively  little  oxygen,  this  particular  frac- 
tion of  the  oxygen  is  in  precise  consideration  of  the  greater 
importance,  for  the  tissue  cells  do  not  come  in  direct  contact 
with  the  oxygen-bearing  red  blood  corpuscles,  but  with  the 
plasma  only.  The  erythrocytes  serve  as  a  reservoir  from 
which  the  plasma-oxygen  is  continuously  supplied. 

Tension  Curves. — The  intake  of  oxygen  into  the  blood 
naturally  depends  to  a  very  marked  degree  upon  the  oxygen 
pressure  in  the  air.  For  each  given  pressure  there  cor- 
responds a  definite  amount  of  fixed  oxygen.  By  taking  the 
pressures  as  abscissas  and  the  corresponding  amounts  of 
oxygen  taken  into  the  blood  as  ordinates,  a  tension  curve 
may  be  constructed.  The  course  of  the  curve  indicates  how 
much  oxygen  is  combined  by  the  haemoglobin  at  a  given 
pressure.  If  the  total  amount  of  oxygen  in  a  unit  volume 
of  blood  be  known  for  this  particular  moment,  it  is  possible 
to  come  to  a  conclusion  as  to  the  amount  which  is  fixed  by 
the  affinities  of  haemoglobin  and  how  much  is  available  in 
free  state. 

The  general  type  of  such  tension  curves  is  always  the 
same  in  all  sorts  of  blood  and  haemoglobin  solutions.  In- 
variably the  line  is  that  of  a  curve  with  its  concavity  toward 
the  axis  of  the  abscissa,  sharply  ascending  and  then  continu- 
ing asymptomatically,  this  being  expression  of  the  fact 
that  the  fixed  amount  of  gas,  as  the  pressure  is  gradu- 
ally raised,  increases  far  more  quickly  at  a  slight  pressure 
than  at  higher  pressure.  Even  at  an  oxygen  pressure  of 
160  mm.  which  about  corresponds  to  the  partial  pressure 
normal  for  the  atmospheric  oxygen,  the  haemoglobin  seems 
to  be  within  a  slight  percentage  of  saturation  with  oxygen. 
The  maximal  capacity  for  oxygen  fixation  both  of  fresh  blood 
and  of  haemoglobin  solutions  prepared  by  different  methods 
has  been  found  by  Hufner,  and  a  number  of  other  inves- 


INFLUENCE  OF  TEMPERATURE  589 

tigators  as  well,  to  be  1.34  cubic  centimetres  of  oxygen  for 
one  gram  of  haemoglobin.22 

If  the  course  of  the  pressure  curves,  however,  is  more 
closely  inspected,  marked  differences  will  be  noted  on  com- 
parison of  normal  laked  blood  and  solutions  of  isolated 
haemoglobin  obtained  from  different  animal  species  and  in- 
dividuals, which  have  led  Bohr  and  his  followers  to  assume 
the  existence  of  a  multiplicity  of  haemoglobins  and  particu- 
larly to  differentiate  ' l  haemochrome  "  from  haemoglobin. 

As  a  matter  of  fact,  the  line  of  the  tension  curves  may 
be  influenced  by  a  number  of  physical  and  chemical  factors.23 

Influence  of  Carbonic  Acid  Pressure. — As  one  of  the  most 
important  factors  of  this  type  we  have  come  to  recognize 
carbonic  acid.  According  to  the  studies  of  Bohr,  Hassel- 
bach and  Krogh  the  ascent  of  the  curve  becomes  the  less 
sharp  the  greater  the  quantity  of  carbonic  acid  in  the  blood. 
Given  the  same  oxygen  pressure,  there  will  be  less  oxygen 
fixed  the  more  carbonic  acid  there  is  present;  this  may  be 
expressed  in  other  words  by  saying  that  carbonic  acid  may 
raise  the  dissociation  pressure  of  oxyhemoglobin,  that  is, 
increase  its  tendency  to  give  off  oxygen.  We  are  here  deal- 
ing with  a  purposeful  provision  of  the  economy  which  makes 
it  possible  to  have  an  especially  ready  oxygen  release  from 
the  arterial  blood  at  precisely  such  places  where  for  any 
reason  carbonic  acid  accumulates  in  the  tissues  and  where 
a  danger  from  oxygen  impoverishment  is  threatened. 

Influence  of  Temperature. — Another  important  factor  in 
connection  with  oxygen  tension  is  the  temperature  (as  shown 
by  the  experiments  of  Paul  Bert,  Barcroft,  Löwy  and  Cas- 
pari).  The  power  of  taking  up  oxygen  by  haemoglobin  is 
diminished  with  increase  of  temperature.  In  increased 
temperature  from  fever  or  from  severe  muscular  exertion, 

22  Cf .  Literature :  O.  Cohnheim,  Chemie  der  Eiweisskörper,  III  Ed.,  p.  343, 
1911. 

23  Literature  upon  the  Dissociation  of  Oxyhemoglobin :  Ch.  Bohr,  Nagel'a 
Handb.  d.  Physiol.,  1,  57-68,  70-103,  1905;  A.  Löwy,  Handb.  d.  Biochem.,  4', 
47-55,  1908. 


590  THE  GASES  OF  THE  BLOOD 

therefore,  the  oxygen  supply  to  the  tissue  is  favored  by 
increased  dissociation  of  the  oxyhemoglobin.24  According 
to  Hasselbach  25  a  transitory  lowering  of  the  oxygen  fixing 
power  of  the  blood  can  be  produced  by  lowering  of  the 
atmospheric  pressure. 

Influence  of  the  Salts  in  the  Medium,  and  Other  Factors. 
— The  saline  constituents  of  the  medium  are  also  un- 
doubtedly of  much  physiological  importance.  If  a  ten 
per  cent,  haemoglobin  solution  in  one  per  cent,  soda  solu- 
tion be  prepared  the  oxygen  fixation  is  apparently  firmer 
than  in  blood  under  comparable  conditions.26  Barcroft  and 
his  colleagues  27  have  concluded  that  the  course  of  the  pres- 
sure curve  is  so  highly  dependent  upon  the  nature  and  con- 
centration of  the  salts  of  the  surrounding  medium,  that  we 
can  scarcely  contemplate  the  formulation  of  a  generally 
applicable  dissociation  curve.  If  an  examination  be  made, 
for  example,  of  one  and  the  same  haemoglobin  dissolved  in 
distilled  water,  in  0.7  per  cent,  salt  solution,  and  0.9  per 
cent,  calcium  chloride  solution,  and  in  the  presence  of  sodium 
bicarbonate  or  sodium  monophosphate,  altogether  different 
pressure  curves  result.  By  adding  the  salts  which  belong 
in  the  corresponding  blood  corpuscles  to  a  solution  of  dog 
(or  human)  haemoglobin  the  characteristic  curve  for  the 
particular  blood  will  be  obtained. 

Physical-chemical  Conception  of  Oxygen  Fixation  by 
Hämoglobin. — The  entrance  of  lactic  acid  into  the  blood  may 
also  distinctly  modify  the  course  of  the  curve  of  oxygen 
pressure.  According  to  Barcroft  more  favorable  conditions 
for  the  supply  of  oxygen  to  the  tissues  are  likely  to  obtain 
at  great  heights  because  of  diminution  of  the  blood 
alkalescence. 


24  Cf.  A.  Durig,  Handwörterb.  d.  Natur  wissensch.,  Jena,  G.  Fischer,  1,  692. 

26  K.  A.  Hasselbach,  Festschr.  0.  Hammersten,  Wiesbaden,  1906;  cited  in 
Jahresber.  f.  Tierchemie,  36,  166,  1906. 

28  Cf.  A.  Löwy,  Handb.  d.  Biochem.,  4',  52,  1908. 

27  J.  Barcroft,  with  Camis  and  Roberts,  Jour,  of  Physiol.,  39,   118,   143, 
1909. 


OXYGEN  FIXATION  591 

Sufficient  has  been  said  to  indicate  that  very  complex 
conditions  prevail  in  connection  with  the  fixation  of  oxygen 
by  haemoglobin  and  that  it  is  scarcely  possible  to  express 
these  by  a  simple  formula.     For  a  long  time  the  Hüfner 

formula,  c0  =  K  Cr ^-^»   was  popular   (Co  representing  the 

760 

amount  of  oxyhemoglobin,  Cr  that  of  reduced  haemoglobin, 
K  a  constant,  p0  the  oxygen  tension  at  the  surface  of  the  solu- 
tion, and  at  the  absorption  coefficient  at  temperature,  t). 
Later,  however,  objections  from  various  sources  have  been 
raised  against  this  formula.  Thus  Bohr  assumes  in  the  first 
place  that  while  the  combination  of  iron-free  globin  with 
iron-containing    haemochromogen    may    be    hydrolytically 

H  G  F 

dissociated  (Haemoglobin  ±^ Globin  +  Haemochromogen)  •, 
on  the  other  hand  there  may  be  an  equilibrium,  F0  *£  F  + 
20o,  F0  representing  the  iron-containing  haemoglobin  frac- 
tion combined  with  oxygen.  From  this  assumption  Bohr 
arrives  at  a  rather  complicated  formula  of  dissociation.28  V. 
Henri  believes  that  we  may  more  satisfactorily  harmonize 
theory  and  practice  by  assuming  that  two  molecules  of  hae- 
moglobin unite  with  one  molecule  of  02.29  Manchot 30  is  of 
the  opinion  that  haemoglobin  is  capable  of  combining  oxygen 
and  other  gases  in  the  same  way  that  sulphate  of  iron  com- 
bines nitrous  oxide  or  chlorate  of  copper  fixes  carbon  mon- 
oxide, and  holds  that  the  laws  of  equivalence  and  mass  action 
are  sufficient  to  explain  the  complex  phenomena,  Barcroft 
and  Hill31  regard  it  as  almost  beyond  doubt  that  dissocia- 
tion of  oxyhemoglobin  takes  place  in  accord  with  the  equa- 
tion, Hb  +  02,±^:Hb02,  and  follows  the  law  of  mass  action; 
has  a  high  temperature  coefficient  and  increases  four-fold 

28  Cf .  A.  Löwy,  Handb.  d.  Bioehem.,  4',  53-54,  1908 ;  B.  v.  Reinbold,  XVI 
intemat.  Mediz.  Kongress,  Budapesth,  1909,  S.  A. 

29  V.  Henri,  C.  R.  Soc.  de  Biol.,  56,  339,  1904. 

30  W.  Manchot  (Chem.  Instit.,  Würzburg),  Ann.  d.  Chem.,  370,  241,  1910; 
572,  179,  1910. 

81  J.  Barcroft  and  A.  V.  Hill  (Physiol.  Lab.,  Cambridge),  Jour,  of  Physiol.,. 
39,  411,  1910. 


592  THE  GASES  OF  THE  BLOOD 

for  every  10°  rise  of  temperature.  However,  W.  Ostwald 32 
looks  on  the  whole  problem  from  an  entirely  different  stand- 
point, introducing  in  opposition  to  the  theory  of  dissoci- 
ation and  chemical  combination  a  theory  of  adsorption, 
and  expressing  the  belief  that  the  complex  phenomena  of 
gas  fixation  in  the  blood  are  far  better  regarded  as  purely 
physical  adsorption  phenomena  and  that  they  can  be  dealt 
with  mathematically  by  means  of  the  formula  of  adsorption. 
The  author  is  not  in  a  position  to  form  a  personal  opinion 
in  regard  to  this  difficult  subject  and  believes  it  best  to  await 
with  patience  the  future  conclusions  of  physical  chemists  in 
this  problem. 

Similar  differences  of  opinion  obtain  as  to  the  physical- 
chemical  interpretation  of  carbon  monoxide  haemoglobin, 
nitrous  oxide  haemoglobin,  cyanhsemoglobin,  sulphhsemoglo- 
bin  and  acetylenehsemoglobin.  It  is  scarcely  likely  to  be 
regarded  as  appropriate  here  to  spend  any  time  on  the 
length  and  breadth  of  this  subject  and  in  the  end  come  to  no 
satisfactory  conclusion.  It  should  be  sufficient  to  call  atten- 
tion to  the  authoritative  statements  which  may  be  found  in 
the  papers  of  Ch.  Bohr,  A.  Löwy,  and  F.  Müller.33 

Carbonic  Acid  Combination  in  the  Blood. — Turning  now 
to  the  consideration  of  carbonic  acid  combination  in  the 
blood,  we  approach  a  subject  of  even  more  complicated 
character  than  that  of  oxygen  fixation,  as  carbonic  acid 
enters  into  combinations  subject  to  dissociation  with  the 
inorganic  as  well  as  with  organic  constituents  of  the  blood. 
Important  researches  upon  this  subject  have  been  prose- 
cuted by  Pflüger,  Gaule,  Setschenow,  Zuntz  and  A.  Löwy, 
Bohr,  Torup,  Jaquet,  Nagel  and  others.34 

A  portion  of  the  carbonic  acid  exists  in  the  blood  as 

32  W.  Ostwald,  Zeitschr.  f.  Kolloidchem.,  2,  264,  294,  1908;  cited  in 
Jahresber.  f.  Tierchemie,  38,  187,  1908. 

33  Ch.  Bohr,  Nagel's  Handb.  d.  Physiol.,  1,  120-128,  1905;  A.  Löwy,  Handb. 
d.  Biochem.,  4',  43-44,  65-71,  1908;  F.  Müller,  ibid.,  1,  681-706,  1909;  Handb. 
d.  biochem.  Arbeitsmethod.,  3',  664-703,  1910. 

34  Literature  upon  Carbonic  Acid  Combination  in  the  Blood:  Ch.  Bohr, 
Nagel's  Handb.  d.  Physiol.,  1,  68-69,  103-117,  1905;  A.  Löwy,  Handb.  d. 
Biochem.,  If',  55-64,  77,  1908. 


CARBONIC  ACID  COMBINATION  593 

alkali  carbonate,  and  as  such  is  subject  to  hydrolytic  disso- 
ciation in  accordance  with  the  law  of  mass  action :  Na2C03  + 
H2C03^±:2NaHC03.  While  from  a  solution  of  bicarbonate 
of  the  same  concentration  as  in  the  blood  only  about  one 
quarter  of  the  total  carbonic  acid  can  be  withdrawn  even  by 
pumping  all  day  long,  if  blood  be  subjected  to  the  vacuum 
of  a  pump  the  whole  amount  of  carbonic  acid  is  freed  within 
but  a  few  hours.  This  remarkable  feature  is  explained  by 
the  fact  that  there  are  substances  of  an  acid  character  con- 
tained in  the  blood  which  displace  the  carbonic  acid  with 
the  assistance  of  the  vacuum.  Further  analysis  of  this 
phenomenon  has  shown  that  the  carbonic  acid  is  withdrawn 
more  slowly  from  the  serum  alone  than  from  the  general 
blood:  the  latter  therefore  contain  substances  manifesting 
acid  characteristics  in  higher  degree.  These  substances  of 
acid  character  with  which  we  are  here  concerned  are  the  hae- 
moglobin and  other  proteins  of  the  blood.  We  may  conceive 
that  the  carbonic  acid  and  protein  of  acid  type,  and  other 
acids  which  gain  access  to  the  blood,  as  lactic  acid,  are  in 
competition  for  the  possession  of  the  blood  alkali  and  ap- 
portion it  among  themselves  in  accordance  with  the  law  of 
mass  action.  But  the  situation  is  still  more  complicated  by 
the  fact  that  the  proteins  have  the  dual  nature  of  acids  and 
bases ;  and  not  only  may  be  capable  of  combining  alkali  to 
their  carboxyl,  but  may  be  capable  of  fixing  acids  to  their 
ammonia  rests,  among  them  carbonic  acid.  The  two  proc- 
esses may  go  on  at  the  same  time ;  but  it  should  be  added 
that  a  relatively  high  carbonic  acid  pressure  is  required  in 
order  to  separate  haemoglobin  from  its  alkaline  combina- 
tions, but  that  combination  between  haemoglobin  and  car- 
bonic acid  can  take  place  even  where  the  carbonic  acid  pres- 
sure is  low.  This  last  feature  is  apparently  of  the  greater 
physiological  significance. 

What  is  the  nature  of  the  combination  of  carbonic  acid 
with  haemoglobin?  While,  as  has  been  seen,  the  intake  of 
oxygen  into  haemoglobin  is  markedly  influenced  by  the  pres- 

38 


594  THE  GASES  OF  THE  BLOOD 

ence  of  carbonic  acid,  in  the  reverse  carbonic  acid  combina- 
tion proves  to  be  relatively  independent  of  the  degree  of 
oxygen  saturation  of  the  haemoglobin.35  From  this  it  has 
been  concluded  that  carbonic  acid  enters  into  combination 
with  the  globin  component,  not  the  haematin,  of  the  haemo- 
globin. 

In  the  matter  of  the  nature  of  the  combination  of  car- 
bonic acid  with  proteins,  Siegfried's  carb amino reaction  (v. 
Vol.  I  of  this  series,  pp.  86-88,  Chemistry  of  the  Tissues) 
seems  suited  to  furnish  some  suggestion.  The  statement 
may  be  recalled  that  aminoacids  are  capable  of  loosely  fixing 
carbonic  acid  in  accordance  with  the  equation : 

COOH  COOH 

Siegfried,  basing  his  views  upon  observations  upon  Poly- 
peptids, believes  that  any  place  in  the  body  where  protein 
and  carbonic  acid  combine,  the  latter  is  fixed  as  above ;  from 
which  standpoint  the  observations  upon  C02  fixation  in  the 
blood,  especially  those  of  Sertoli,  Setschenow,  Bohr  and 
others,  appear  in  a  new  light.36 

Process  of  Exchange  Between  the  Bloods  Corpuscles  and 
Serum. — The  proteid  substances  are  contained  in  the  blood 
partly  in  alkaline  combinations,  and  there  can  be  no  doubt 
that  when  carbonic  acid  comes  in  contact  with  them  a  por- 
tion of  the  alkali  is  withdrawn  through  the  mass  action  of 
the  carbonic  acid.  The  increase  in  the  amount  of  diffusible 
alkali  in  the  blood  serum  which  has  been  noted  by  N.  Zuntz 
and  A.  Löwy  and  by  L.  Fredericq  when  carbonic  acid  is 
introduced  into  the  blood,  finds  an  explanation  from  this 
view,  Zuntz  assuming  that  alkaline  carbonate  passes  in  this 
way  from  the  blood  cells  into  the  plasma.  Hamburger  has, 
however,  observed  that  coincidently  with  this  the  chlorine 

85  A.  Löwy,  Handb.  d.  Biochem.,  4'>  56,  1908,  ascribes  some  ability,  even 
though  but  small,  to  oxygen  to  displace  carbonic  acid  from  the  blood. 

36 M.  Siegfried  (Leipzig),  in  collaboration  with  C.  Neumann  and  H. 
Liebermann,  Zeitschr.  f.  physiol.  Chem.,  J,Jh  85,  1905;  46,  401,  1905;  5Jt,  423, 
437,  1908. 


MECHANISM  OF  GAS  EXCHANGE       595 

proportion  of  the  serum  diminishes.  Gürber  attempts  to 
explain  the  process  by  supposing  that  hydrochloric  acid  is 
separated  from  the  sodium  chloride  by  the  mass  action  of 
the  carbonic  acid  (NaCl  +  H2C03  =  HC1  +  NaHC03),  the 
hydrochloric  acid  becoming  fixed  in  the  blood  cells  and  the 
carbonate  remaining  in  the  serum.  Koppe  in  turn  assumes 
more  complicated  processes  of  wandering  of  the  ions.  Who- 
ever is  particularly  interested  in  this  question  may  find  full 
information  in  the  excellent  work  of  Hamburg  (" Osmoti- 
scher Druck  und  Ionenlehre").37  "However  we  may  the- 
oretically regard  them,"  say  A.  Löwy,  "the  processes  of 
interchange  between  the  blood  cells  and  the  serum  con- 
stantly indicate  the  existence  of  some  important  means  of 
regulation  with  the  purpose  of  maintaining  the  carbonic 
acid  tensions  in  the  body  at  as  low  and  unharmful  a  level 
as  possible. ' ' 

GAS  EXCHANGE  IN  THE  LUNG 

We  may  here  turn  to  the  much  discussed  question  of  the 
kind  of  forces  by  which  the  gas  exchange  takes  place  in  the 
lungs.  Bohr  and  his  followers  for  a  long  time  have  main- 
tained the  view  that  the  purely  physical  processes  of  dif- 
fusion are  not  sufficient  to  explain  the  phenomena,  and  that 
it  is  essential  to  ascribe  to  the  endothelial  cells  of  the  alveoli 
the  ability  to  functionate  as  secretory  elements. 

Mechanism  of  Gas  Exchange. — Any  extensive  historical 
development  of  the  general  question,  upon  which  a  great 
sum  of  most  subtile  physiological  work  has  been  expended, 
may  be  the  more  appropriately  dispensed  with,  as  the 
matter  at  issue  seems  at  present  to  be  finally  settled.  The 
most  recent  studies  upon  this  subject,  those  of  Leon  Fred- 
ericq,  Douglas  and  Haldane,38  R.  duBois-Reymond,39  and 

"Literature:  Hamburger,  Osmotischer  Druck  und  Ionenlehre,  1,  291 
et  seq.,  Wiesbaden,  1906;  A.  Löwy,  Handb.  d.  Biochem.,  Jf',  63-64,  1908. 

38  L.  Fredericq,  Arch,  internat.  de  Physiol.,  10,  391,  1911;  J.  S.  Haldane 
and  C.  G.  Douglas  (Oxford),  VIII  internat.  Physiol.  Kongr.,  Wien,  Sept., 
1910;  Proc.  Roy.  Soc.,  82B,  331,  1910;  cited  in  Biochem.  Centralbl.,  10,  No. 
2633 ;  Proc.  Roy.  Soc,  84B,  568. 

39 R.  duBois-Reymond  (Berlin),  Arch.  f.  (Anat.  u.)  Physiol.,  1910,  257; 
Berliner,  physiol.  Ges.,  July  2,  1909;  Centralbl.  f.  Physiol.,  23,  953. 


596  GAS  INTERCHANGE  IN  LUNGS 

particularly  those  of  Krogh,40  a  pupil  of  Bohr's,  all  agree 
that  both  the  absorption  of  oxygen  and  the  separation  of 
carbonic  acid  in  the  lungs  normally  takes  place  exclusively 
by  diffusion,  and  that  the  assumption  of  special  vital  forces 
regulating  the  gas  exchange  has  become  superfluous.  Hal- 
dane  and  Douglas  alone41  believe  that  if  (as  in  carbon 
monoxide  poisoning,  in  violent  muscular  exercise,  and  in 
case  of  oxygen  deficiency  in  the  respired  air)  there  occurs 
a  deficiency  of  oxygen  in  the  tissues,  through  a  regulatory 
process  the  oxygen  is  secreted  by  active  forces ;  that  in  this 
way  the  oxygen  tension  in  the  arterial  blood  is  apparently 
distinctly  raised  above  that  of  the  air  in  the  pulmonary 
alveoli,  which  could  not  be  reconciled  with  ideas  of  processes 
of  simple  diffusion.  R.  duBois-Reymond,  however,  notes 
in  answer  to  this  that  if  normally  the  gas  exchange  is  the 
result  of  simple  diffusion,  it  would  not  be  easy  to  see  how 
the  pulmonary  epithelial  cells  may  be  supposed  to  suddenly 
acquire  a  power  of  gas  secretion;  that  aside  from  this  the 
histological  appearances  give  no  basis  for  ascribing  to  these 
cells  any  such  activity.  It  may  therefore  be  held  that  we 
are  fully  justified  in  dropping  the  hypothesis  of  gas  secre- 
tion by  the  pulmonary  epithelium. 

Secretion  of  Oxygen  in  the  Swim-bladder  of  Fish. — We 
know  from  comparative  physiology  of  an  unmistakable 
example  of  undoubted  oxygen  secretion  actually  performed 
by  an  organ  in  nature;  this  is  the  swim-bladder  of  fishes. 
Long  ago  Biot  was  struck  by  the  fact  that  the  gas  filling  the 
swim-bladder  (an  organ  apparently  primarily  serving  hy- 
drostatic purposes)  may  consist  largely  of  oxygen;  and  this 
is  true  particularly  of  fishes  which  come  from  the  deeper 
sea  levels.  When  it  is  recalled  that  the  partial  pressure 
of  oxygen  within  the  swim-bladder  in  marked  depths  may 

40  A.  Krogh,  Skandin.  Arch.  f.  Physiol.,  23,  248,  1910;  cf.  also  P.  Trendelen- 
burg (Zoöl.  Station,  Naples),  Zeitschr.  f.  Biol.,  57,  495,  1912. 

41 C.  G.  Douglas  and  J.  S.  Haldane  (Physiol.  Lab.,  Oxford),  Jour,  of 
Physiol.,  44,  305>  1912,  and  earlier  contributions. 


CUTANEOUS  RESPIRATION  597 

reach  the  enormous  degree  of  ninety  atmospheres,  while 
that  of  the  surrounding  water  amounts  to  only  about  one- 
fifth  of  an  atmosphere,  it  is  at  once  evident  that  here  there 
can  be  no  possibility  of  a  diffusion  process,  but  that  neces- 
sarily we  are  dealing  with  a  true  oxygen  secretion.  Moreau 
showed  that  if  the  swim-bladder  be  emptied  by  puncture 
with  a  trocar  it  becomes  filled  again  by  secretion  of  a  gas 
consisting  mainly  of  oxygen.  Bohr  was  able  to  prove  that 
this  secretory  process  is  under  the  regulation  of  the  nervous 
system,  and  that  on  section  of  the  intestinal  branches  of  the 
vagus  nerves  it  fails.42 

In  conclusion  it  may  be  well  to  briefly  touch  upon  the 
question  of  the  means  at  disposal  of  the  economy  to  com- 
pensate by  the  function  of  other  organs  for  loss  of  the 
respiratory  work  of  the  lungs. 

Partial  Pulmonary  Exclusion. — Hellin's  experiments  in 
reference  to  unilateral  excision  of  the  lung  may  be  men- 
tioned first,  which  have  attained  a  certain  degree  of  actual 
success,  from  the  prevailing  efforts  of  surgeons  to  bring 
the  lungs  into  the  field  of  accessibility  to  operative  proced- 
ures. Hellin  had  observed  that  rabbits,  one  lung  of  which 
he  had  excised,  usually  bore  the  procedure  well.  The  dysp- 
noea at  first  appearing  generally  disappeared  in  the  course 
of  a  few  hours ;  and,  what  was  even  more  remarkable,  the 
amount  of  eliminated  carbonic  acid,  which  was  obtained  from 
the  single  lung  after  the  operation,  was  quite  as  large  as 
that  which  was  previously  excreted  from  the  two  lungs 
together.  This  was  made  possible  primarily  by  an  increase 
in  the  work  of  the  heart,  which  in  consequence  soon  became 
hypertrophied.  There  later  developed  a  distinct  dilatation 
of  the  blood-vessels  of  the  lung,  and  in  the  end  there  was  a 
distinct  hypertrophy  of  the  alveolar  pulmonary  tissue 
itself.43 

42  Literature  upon  Gas  Secretion  in  the  Swim-bladder :  Ch.  Bohr,  Nagel's 
Handb.  d.  Physiol.,  1,  163-166,  1905;  W.  Cronheim,  Handb.  d.  Biochem.,  4", 
431-432,  1910. 

«D.  Hellin  (Warsaw),  Arch.  f.  exper.  Pathol.,  55,  21,  1906. 


598  GAS  INTERCHANGE  IN  LUNGS 

Cutaneous  Respiration. — While  in  amphibia,  as  is  well 
known,  cutaneous  respiration 44  plays  an  important  function 
and  may  in  fact  replace  the  pulmonary  respiration,  this  is 
altogether  subsidiary  when  we  come  to  deal  with  the  keratin- 
ized epiderm  of  warm-blooded  animals.  According  to  the 
coinciding  investigations  of  Eegnault  and  Reiset,  Ziilzer, 
Bohr  and  others,  the  skin  at  best  cooperates  to  the  extent 
of  one  per  cent,  of  the  total  gas  exchange.  This  has  been 
confirmed,  too,  by  recent  studies  in  Zuntz's  Institute,45  in 
which  the  arm  of  the  experiment  subject  was  surrounded 
by  a  gas  mixture  containing  about  ninety  per  cent,  of  oxygen 
in  a  closed  glass  sleeve,  and  the  oxygen  consumption  de- 
termined. The  results  showed  again  (extending  the  calcu- 
lation to  the  entire  body  surface)  that  the  intake  of  oxygen 
by  the  skin  does  not  exceed  about  one  per  cent,  of  that  by 
the  lungs.  The  severe  lesions,  perhaps  fatal,  which  are  met 
in  animals  in  which  the  most  of  the  skin  has  been  varnished, 
are  certainly  therefore  not  due  to  a  fault  of  the  cutaneous 
respiration.  (Usually  these  are  regarded  as  connected  with 
the  marked  chilling  of  the  animals ;  yet  there  are  cases  in 
which  this  explanation  is  insufficient.  The  latter  have  led 
Babäk  and  other  authors  to  revive  the  old  supposition  of 
an  accumulation  of  some  unknown  poisonous  material  within 
the  body;  but  nothing  positive  is  known  about  it.) 

Oxygen  is  absorbed  much  better  by  the  serous  mem- 
branes than  by  the  skin.  Thus  0.  Pascucci  has  proved  by 
certain  admirable  experiments  that  guinea-pigs  are  able  to 
remain  alive  in  an  atmosphere  of  nitrogen,  if  oxygen  be 
furnished  to  them  intraperitoneally.46 

Intestinal  Respiration. — An  exchange  of  gases  may  also 
take  place  in  the  intestinal  wall  between  the  intestinal  con- 

44  Literature  upon  Cutaneous  Respiration :  Ch.  Bohr,  Nagel's  Handb.  d. 
Physiol.,  1,  160-163,  217-218,  1905;  A.  Löwy,  Handb.  d.  Biochem.,  4',  167-171, 
1908. 

46 G.  Franchini  and  L.  Preti  (Lab.  of  N.  Zuntz),  Biochem.  Zeitschr.,  9, 
442,  1908. 

46 O.  Pascucci  (Luciani's  Lab.,  Rome),  Arch,  per  le  Scienze  med.,  S3,  347, 
1909. 


MOUNTAIN  LABORATORIES  599 

tents  and  the  blood,  although  this  is  in  general  not  a  matter 
of  physiological  importance.  There  exist  certain  fishes  (mud 
lamprey,  Cobitis  fossilis,  and  some  others)  which  have  a 
proper  intestinal  respiration.  In  such  instances  the  mid- 
intestine  seems  by  the  marked  development  of  the  network 
of  capillaries  in  its  walls  and  by  a  peculiar  type  of  epithelium 
to  have  acquired  adaptation  for  a  respiratory  function  to 
such  a  degree  as  to  actually  enable  the  animals  to  provide 
from  the  intestine  a  part  of  their  oxygen  requirements  from 
the  air  that  has  been  swallowed. 

PHYSIOLOGY  OF  ALPINISM 

In  connection  with  the  discussion  of  the  processes  of  gas 
interchange,  a  brief  excursion  into  the  field  of  those  phe- 
nomena which  we  customarily  include  under  the  term 
"physiology  of  alpinism"  may  be  permitted.47  It  would 
scarcely  be  appropriate  to  entirely  neglect  the  extensive 
literature  occupied  by  investigations  upon  this  subject. 
Nevertheless  the  author  does  not  hesitate  to  confess  that 
he  would  not  care  to  attempt  to  find  a  way  through  the 
labyrinth  of  contradictory  and  confusing  observations,  in 
which  everyone  who  ventures  into  these  matters  finds  him- 
self at  once  ensnared,  were  it  not  that  one  of  the  best- 
informed  experts  in  the  subject,  A.  Durig,48  has  recently 
treated  the  problem  comprehensively  and  in  such  a  manner 
that  his  statements  may  serve  as  a  welcome  guide. 

Sources  of  the  Observation  Material. — To  the  Italian 
physiologist,  Angelo  Mosso,  belongs  the  credit  of  having 
by  his  personal  initiative  made  possible  the  construction  of 
an  observatory  adapted  to  physiological  studies  at  high 
altitudes,  Capanna  Margherita,  situated  at  an  altitude  above 

47  Literature  upon  the  Physiology  of  Alpinism:  A.  Mosso,  Der  Mensch  auf 
den  Hochalpen,  Leipzig,  Pub.  Veit  &  Co.,  1899 ;  A.  Jaquet,  Ergebn.  d.  Physiol., 
2',  521-531,  1903;  O.  Cohnheim,  ibid.,  2',  61"2-638,  1903;  Ch.  Bohr,  Nagel's 
Handb.  d.  Physiol.,  1,  210-216,  1905;  Kronecker,  Die  Bergkrankheit,  Deutsche 
Klinik,  11,  17-146,  1907;    A.  Löwy,  Handb.  d.  Biochem.,  J/,  199-231,  1908. 

48  A.  Durig,  Wiener  klin.  Wochenschr.,  24,  No.  18. 


600  PHYSIOLOGY  OF  ALPINISM 

sea-level  of  4500  metres  on  Monte  Rosa,  and  of  having  thus 
provided  means  for  systematic  studies  in  this  field.  The 
Mosso  Institute,  situated  at  a  height  of  about  3000  metres 
on  Colle  d'Olen,  conducted  by  Aggazzoti,  makes  it  possible 
to  combine  observations  made  at  different  heights  from  the 
sea-level,  and  supplement  each  other.  Thanks  to  a  series  of 
scientific  Monte  Rosa  expeditions  conducted  by  N.  Zuntz, 
A.  Löwy,  A.  Jaquet,  A.  Durig,  and  O.  Cohnheim,49  an  im- 
portant amount  of  observation  material  has  been  collected 
to  date.  This  has  been  supplemented  by  many  earlier  ob- 
servations, by  the  investigations  of  an  expedition  to  Ten- 
eriffe  made  by  Durig,  H.  v.  Schrötter  and  Zuntz,50  by 
observations  by  Douglas,  Haidane,  Y.  Henderson,  and 
Schneider  at  the  top  of  Pike's  Peak  in  Colorado,51  by  a 
number  of  balloon  ascents  made  for  physiological  pur- 
poses,52 and  by  experiments  in  the  pneumatic  cabinet. 

It  is  well  known  that  in  many  human  beings,  as  soon  as 
they  have  attained  a  certain  height  above  the  level  of  the 
sea,  the  symptoms  of  "mountain  sickness"  set  in.  The 
rather  manifold  and  varying  symptom  complex  of  this  con- 
dition has  been  thoroughly  described  by  Angelo  Mosso  in 
his  work,  "Der  Mensch  auf  den  Hochalpen."  53  It  was  be- 
lieved most  probable  that  the  whole  symptom  complex  was 
to  be  classed  as  due  to  oxygen  diminution  in  the  respired 
air.     It  was  essential,  however,  in  order   to    reasonably 

«Shumburg  and  N.  Zuntz  (1895)  ;  A.  Löwy,  J.  Löwy:  L.  Zuntz  (1896)  ; 
Jaquet   and   Stähelin    (1900);    N.   Zuntz,   A.   Löwy,   F.   Müller   and   Caspari 

(1901);  Durig  and  Zunz  (1903)  ;  Durig  (1905);  cf.  Literature:  A.  Löwy, 
Handb.  d.  Biocbem.,  4',  225,  1908;  A.  Durig,  Pflüger's  Arch.,  113,  1906;  A. 
Durig  in  collaboration  with  W.  Kolmer,  R.  Rainer,  H.  Reichel  and  W.  Caspari 

(1906),  Denkschr.  d.  Wiener  Akad.,  86,  1909;  A.  Durig  and  N.  Zuntz.,  Biochem. 
Zeitschr.,  39,  435,  1912;  O.  Cohnheim,  Commissioner  of  Health  Kreglinger  and 
Medical  Student  Kreglinger,  Zeitschr.  f.  physiol.  Chem.,  63,  413,  1909;  O.  Cohn- 
heim, G.  Kreglinger,  L.  Tobler,  O.  H.  Weber,  ibid.,  78,  62,  1912. 

60  A.  Durig,  H.  v.  Schrötter,  N.  Zuntz,  Biochem.  Zeitschr.,  39,  421,  1912. 

61  C.  G.  Douglas,  J.  S.  Haldane,  Y.  Henderson  and  E.  C.  Schneider,  Proc. 
Roy.  Soc,  LXXXV,  65B,  1912;  cited  in  Centralbl.  f.  d.  ges.  Biol.,  13,  No.  1196, 
1912. 

B2Hallion  and  Tissot,  1901;  H.  v.  Schrötter  and  N.  Zuntz.  1902. 

B  A.  Mosso,  Der  Mensch  auf  den  Hochalpen,  Leipzig,  Pub.  Veit  &  Co.,  1899. 


INCREASE  OF  BLOOD  CORPUSCLES      601 

arrange  the  observation  material,  as  a  preliminary  to  elim- 
inate all  the  factors  connected  with  fatigue,  cardiac  over- 
exertion, and  the  like.  The  amount  of  influence  of  climatic 
factors  was,  however,  necessarily  to  be  included  in  the  study. 

Influence  of  Climatic  Factors. — In  the  first  place  the 
effects  of  cold,  which  is  very  appreciable  at  great  heights, 
are  to  be  thought  of ;  but  it  should  be  remembered  that  the 
maintenance  metabolism  in  Greenland  was  not  found  any 
greater  than  in  the  tropics  and  that,  as  Durig  remarks, ' '  the 
vital  flame  does  not  burn  any  more  briskly  under  the  in- 
fluence of  cold  than  in  the  sun-browned  Indians. ' '  A  number 
of  other  climatic  factors,  as  the  wind,  rarefaction,  the  ioniza- 
tion and  electrical  potentials  of  the  atmosphere  have  no 
more  definite  effect  upon  metabolism,  as  far  as  can  be  recog- 
nized. Therefore  the  fall  in  oxygen  pressure  necessarily 
must  be  regarded  as  the  most  important  item  for  consi- 
deration.54 

Increase  of  Blood  Corpuscles. — One  of  the  most  striking 
alterations  developing  in  elevated  climatic  conditions  is  the 
increase  in  the  number  of  red  blood  corpuscles  in  the  unit 
of  volume  of  a  sample  of  withdrawn  blood.  At  present  the 
majority  of  writers  incline  to  the  assumption  that  this  is  not 
an  actual  increase,  but  that,  as  Zuntz  believes,  either  the 
distribution  of  the  corpuscles  is  so  altered  that  a  larger 
proportion  of  them  are  accumulated  in  the  dilated  dermal 
capillaries,  or  on  the  other  hand  there  exists  a  concentra- 
tion of  the  blood  as  the  result  of  a  passage  of  fluid  from  the 
vessels  (which  might  be  thought  of  as  connected  in  the  first 
place  with  an  increased  evaporation  or  in  the  second  place 
with  a  process  of  forcing  the  plasma  out  from  the  action 
of  vasomotor  factors).  That  rapidly  developed,  transitory 
changes  of  the  blood,  such  as  for  example  have  been  ob- 
served inside  of  an  hour  in  a  balloon  ascension,  may  reason- 
ably be  related  with  causes  of  such  a  character,  can  scarcely 
be  doubted.    That  a  more  protracted  sojourn  on  mountain 

M  Cf.  A.  Löwy,  Deutsche  Med.  Wochenschr.,  1904,  121. 


602  PHYSIOLOGY  OF  ALPINISM 

heights  brings  about  an  actual  increase  in  the  total  haemo- 
globin is  a  view  adopted  by  many  authors.  Thus,  for  ex- 
ample, C.  Foa  holds  that  there  is  new  formation  of  red 
blood  cells,  with  a  heightened  activity  of  the  bone  marrow. 
Durig  believes  a  final  decision  of  the  question  will  not  be 
had  until  our  methods  of  determining  the  total  haemoglobin 
and  the  total  capacity  of  oxygen  combination  are  perfected ; 
he  calls  attention  to  the  fact  that  chlorosis  is  not  cured  by 
high  climate  without  appropriate  treatment  of  other  char- 
acter, and  that  we  do  not  find  after  return  from  the  eleva- 
tion the  least  increase  of  iron  elimination  and  not  a  sign 
of  jaundice,  as  would  be  probable  were  there  any  massive, 
important  destruction  of  red  blood  cells. 

Then,  too,  within  recent  times,  sources  of  error  of  which 
we  had  no  idea  before,  have  come  to  be  recognized.  Thus 
Biirker  was  able  to  prove  that  the  hitherto  commonly  used 
counting  chamber  of  Zeiss  gives  too  high  results  at  a  high 
elevation,  from  the  concentration  of  the  blood  from  increased 
evaporation.  Biirker  has  constructed  a  new  chamber  by 
which  this  error  is  avoided.  With  the  latter  he  found  at  an 
elevation  of  1800  metres  only  a  minor  increase  of  the 
erythrocytes,  of  not  above  five  per  cent.  0.  Cohnheim  and 
his  associates,  in  their  most  recent  investigations  in  the 
Monte  Eosa  district,  conducted  with  great  precision  and 
with  the  employment  of  various  methods,  at  elevations  of 
2900  and  4500  metres  have  failed  to  recognize  in  human 
beings  and  in  the  dog  any  physiologically  important  in- 
crease in  haemoglobin.55 

Changes  in  Cardiac  Activity. — As  is  well  known,  dis- 
turbances in  connection  with  the  cardiac  activity  are  promi- 
nent features  in  the  symptom  complex  of  mountain  sickness ; 
and  it  is  not  always  easy  in  these  very  cases  to  rule  out  the 
factors  connected  with  over-exertion.  Durig,  Zuntz,  and 
their  associates,  found  the  pulse  rate  practically  unchanged 

66  O.  Cohnheim,  G.  Kreglinger,  L.  Tobler  and  O.  H.  Weber,  Zeitschr.  f. 
physiol.  Chem.,  78,  62,  1912;  cf.  therein  the  Literature. 


CHANGES  IN  RESPIRATION  603 

up  to  an  elevation  of  3000  metres  (Colle  d'Olen) ;  at  a 
height  of  4500  metres  at  the  Margherita  cottage,  however, 
an  increased  pulse  frequency  manifested  itself  from  the  day 
of  the  ascent  on,  in  all  the  members  of  the  expedition,  which 
gradually  diminished  somewhat,  but  did  not  fall  to  the 
normally  observed  rate  even  in  the  course  of  a  month,  and 
proved  to  be  independent  of  any  passing  rise  of  temperature ; 
then,  too,  the  pulse  rate  was  persistently  very  changeable. 
After  returning  into  the  valley  this  variability  not  only 
disappeared  at  once,  but  the  pulse  rate  fell  even  below 
normal.  Apparently  we  should  attribute  symptoms  of  this 
character  to  an  abnormality  in  the  function  of  the  vagi. 
The  form  of  the  pulse  curve,  and,  too,  the  blood  pressure 
showed  no  typical  changes,  at  least  wherever  no  overexer- 
iton  had  taken  place. 

Changes  of  Respiration. — The  study  of  the  changes  in 
the  respiratory  activity  occupies  a  very  large  field  in  the 
physiological  literature  upon  alpinism,  as  might  be  sup- 
posed.56 The  economy  has  a  tendency  to  compensate  for 
the  reduction  in  the  partial  pressure  of  oxygen  by  an  in- 
crease of  ventilation ;  thus  in  a  very  large  majority  of  cases 
it  may  be  observed  at  high  elevations  that  the  depth  of 
breathing  increases.  Apparently  the  organism  can  also 
protect  itself  against  a  decrease  in  the  atmospheric  oxygen 
by  a  relative  increase  of  the  amount  of  oxygen  absorbed, 
and  too  by  an  acceleration  of  the  circulation  of  the  blood.57 
Increase  in  the  depth  of  breathing  has,  it  is  true,  been  noted 
by  A.  Löwy  and  F.  Müller  also  at  the  seashore.  On  the 
other  hand,  according  to  Durig,  a  distinct  increase  of  ven- 
tilation effort  begins  to  be  noticeable  only  from  altitudes  of 
3000  metres  and  upwards.  However,  no  basic  type  of 
adaptation  of  the  respiratory  mechanism  can  be  distin- 

66 Literature :  J.  S.  Haldane  and  E.  P.  Poulton  (Physiol.  Lab.,  Oxford), 
Jour,  of  Physiol.,  37,  390,  1908;  R.  O.  Ward,  ibid.,  378;  J.  Barcroft  (Physiol. 
Inst.,  Cambridge),  Jour,  of  Physiol.,  J,2,  44,  1911. 

67  Cf.  J.  Tissot,  Jour,  de  Physiol,  12,  492,  520,  1910. 


604  PHYSIOLOGY  OF  ALPINISM 

guished ;  nor  can  it  be  in  any  degree  predicted  that  sojourn 
at  a  moderate  elevation  will  necessarily  bring  about  pro- 
portionately a  more  powerful  ventilation  of  the  lungs. 

At  very  high  elevations  (above  4500  metres)  the  danger 
of  dyspnoea  undoubtedly  becomes  impending.  Even  trifling 
interference  with  breathing,  as  from  lacing  the  shoes,  may 
call  out  a  feeling  of  oppression,  and  ability  to  perform 
labor  seems  very  much  reduced.  Yet  even  at  a  height  of 
6000  metres,  which  was  attained  by  Whymper  on  Chim- 
borazo,  mountain  sickness  may  fail  to  appear.  In  direct 
connection  with  the  dyspnoea  there  also  occurs  sleepless- 
ness. The  members  of  Himalaya  expeditions,  usually  at 
heights  of  about  6000  metres,  on  going  to  sleep  were  almost 
immediately  wakened  by  dyspnceic  symptoms.  The  breath- 
ing may  even  assume  a  periodic  character,  quite  like  the 
Cheyne-Stokes  type.  The  woman  Himalayan  climber,  Mrs. 
Bullock- Workman,  believes  that  the  greatest  difficulty  at- 
tending the  attainment  of  the  highest  mountain  peaks  of 
the  world  is  the  loss  of  sleep,  as  naturally  the  number  of 
sleepless  nights  increases  with  the  height  of  the  mountain. 

Acapnia. — In  connection  with  mountain  sickness  acapnia 
is  a  subject  which  has  also  been  frequently  discussed.  The 
fact  that  a  stay  in  very  rarefied  air  is  better  sustained  pro- 
vided carbonic  oxide  is  mixed  with  the  respired  atmosphere 
was  proved  some  time  since  by  the  Zuntz  school.  There  is 
reason,  doubtless,  in  this  relation  to  think  that  the  carbonic 
acid,  as  has  been  previously  pointed  out,  may  be  concerned  in 
increasing  the  dissociation  tension  of  oxyhaemoglobin  and 
thus  facilitating  the  suppty  of  oxygen  to  the  tissue.  Accord- 
ing to  the  acapnia  theory  of  Angel  o  Mos  so  the  symptoms 
of  mountain  sickness  may  be  thought  of  as  due,  not  so  much 
to  the  lessened  pressure  of  oxygen,  as  to  a  carbonic  acid 
impoverishment  of  the  blood  and  to  the  loss  of  the  normal 
stimulative  excitation  which  carbonic  acid  exercises  upon 
the  respiratory  centre.  The  demonstrative  force  of  the 
material  brought  forward  by  the  Mosso  school  in  favor  of 


ACAPNIA  605 

this  view  (as  the  contribution  by  B.  Aggazzotti  of  observa- 
tions upon  the  pathological  phenomena,  in  an  orang-outang 
produced  by  rarefaction  of  the  air  and  ameliorated  by  ad- 
ministration of  carbonic  acid)  is  warmly  contested,  how- 
ever, by  others. 

For  the  rest,  certain  experiments  conducted  in  Kron- 
ecker  's  laboratory  show  how  difficult  it  is  to  come  to  a  cor- 
rect interpretation  of  matters  of  this  sort.  It  was  proved 
in  the  first  place  that  rats  and  rabbits  in  atmospheres  of 
pure  oxygen,  if  the  pressure  be  distinctly  diminished,  be- 
come dyspnceic  even  though  the  partial  oxygen  pressure  be 
relatively  high.  In  the  second  place  it  would  appear  that 
the  air  hunger  of  animals  in  rarefied  air  disappear  quite 
as  well  when  the  normal  pressure  conditions  are  produced 
by  addition  of  nitrogen  (instead  of  oxygen).  From  which 
it  may  be  logically  concluded  that  the  dyspnoea  occurring  in 
places  where  the  air  is  rarefied  is  not  primarily  due  so 
much  to  oxygen  deficiency  as  to  a  mechanical  disturbance 
of  the  pulmonary  circulation.58 

A  lowering  of  atmospheric  density  corresponding  to  an 
elevation  of  about  6000  metres  (356  millimetres  of  mer- 
cury) must  in  fact  be  regarded  as  critical,  as  Boycott  and 
Haldane  in  personal  experiments  observed  at  this  grade 
the  appearance  of  cyanosis,  dyspnoea  and  loss  of  conscious- 
ness.59 At  this  degree  of  atmospheric  rarefaction  scarcely 
more  than  half  the  existing  haemoglobin  is  saturated  with 
oxygen  according  to  N.  Zuntz  and  A.  Löwy.  This  agrees 
with  observations  made  in  Graham  Lusk's  laboratory  upon 
dogs  which  were  rendered  unconscious  by  half  saturating 
their  blood  with  carbon  monoxide.60  Similar  experiments 
were  performed  even  earlier  in  Zuntz 's  Institute  by  Frankel, 
Geppert  and  Löwy.  Aggazotti's  orang-outang  became 
apathetic  at  an  atmospheric  pressure  of  about  340  milli- 

68 R.  Frumina,  A.  Rosendahl  (Physiol.  Instit.,  Berne),  Zeitschr.  f.  Biol., 
52,  1,  16,  1909. 

69  A.  E.  Boycott  and  J.  S.  Haldane,  Jour,  of  Physiol.,  37,  355,  190S. 
80  Graham  Lusk,  Ernährung  und  Stoffwechsel,  2nd  Ed.,  p.  239,  1910. 


606  PHYSIOLOGY  OF  ALPINISM 

metres,  and  fell  into  a  sleep-like  state  at  300  millimetres, 
with  the  breathing  of  dyspnoeic  character.61  Zuntz  and 
Levenstein  observed  rabbits  die  after  being  kept  for  several 
days  at  a  barometric  pressure  of  from  300  to  400  millimetres 
under  a  bell-jar ;  autopsy  showed  an  enormous  fatty  degen- 
eration of  the  internal  organs.62 

Loss  in  Alkalescence  of  the  Blood. — The  loss  of  alkales- 
cence of  the  blood  observed  by  Mosso  and  his  pupils  may  be 
regarded  as  directly  related  with  the  oxygen  deficiency  at 
high  elevations.  In  animals  on  Capanna  Margherita  a  loss 
of  30-40  per  cent,  of  blood  alkalinity  was  observed  in  estim- 
ations following  the  Löwy-Zuntz  method ;  a  slighter  loss  of 
alkalinity  was  noted  where  an  analogous  rarefaction  of  the 
air  was  obtained  by  the  air-pump.  It  is  scarcely  a  mistake  to 
attribute  this  diminution  of  alkalescence  to  a  passage  of 
lactic  acid  into  the  blood.63  We  know  since  the  investigations 
of  Araki  that  any  kind  of  oxygen  impoverishment  in  the  body 
leads  to  an  increased  formation  and  eventually,  too,  to  an 
increased  elimination  of  this  acid.64  In  conformity  with  the 
present  attitude  of  science  we  are  justified  in  holding  that 
lactic  acid  may  largely  come  from  destruction  of  sugar. 
That  in  turn  an  accumulation  of  acid  in  the  blood,  by  making 
demands  upon  the  alkali  which  is  usually  combined  with 
carbonic  acid,  is  harmful  to  the  respiratory  function  of  the 
blood  is  obvious.  This  at  once  suggests  a  comparison 
with  the  acid  intoxication  of  diabetic  coma,  although  in  the 
latter  condition  the  materia  peccans  is  not  lactic  acid  but 
ß-oxybutyric  acid.  But,  as  above  stated,  according  to  Bar- 
croft  lactic  acid  facilitates  the  giving  off  of  oxygen  from 
haemoglobin  to  the  tissues.  In  view  of  the  connection  be- 
tween lactic  acid  formation  and  carbohydrate  metabolism 

61  A.  Aggazzotti  (Turin),  Arch.  ital.  de  Biol.,  U,  39,  1905. 

62 G.  Levenstein   (N.  Zuntz's  Lab.),  Pflüger's  Arch.,  65,  278,  1897. 

68  A.  Mosso,  G.  Galeotti,  A.  Aggazzotti,  Arch.  ital.  de  Biol.,  Jfl,  80,  384,  397, 
1904,  and  Rendic  Accad.  dei  Lincei  Roma,  XIII,  XV. 

04  Cf.  P.  v.  Terray  (Physiol.  Instit.,  Budapesth),  Pflüger's  Arch.,  65,  393, 
1897. 


INCREASE  OF  ENERGY  EXCHANGE  607 

it  is  of  considerable  interest  that  according  to  Durig 's  state- 
ments quite  large  dosages  of  grape  sugar  were  consumed 
on  Monte  Rosa  just  as  readily  as  in  the  flat  country  and 
that  ceteris  paribus,  the  respiratory  quotient  manifested 
no  alteration  in  the  former  place. 

Increase  of  Energy  Exchange. — A  very  important  re- 
sultant symptom  of  living  at  high  altitudes  is  the  increase 
of  the  minimal  metabolism.  "By  determining  the  amount 
of  energy  exchange  at  different  altitudes,"  says  Durig,65 
"it  is  plainly  shown  that  at  the  higher  levels  an  increase  of 
the  combustion  processes  appears,  suggested  even  in  the 
lower  elevations.  This  increase  was  present  on  Monte  Rosa 
within  the  first  hour  of  arrival,  and  disappeared  only  on 
our  return  into  the  valley,  suddenly  as  it  had  appeared. 
While  a  flame  burns  more  lively  in  atmospheres  with  the 
richer  supply  of  oxygen,  our  body  exhibits  the  opposite 
behavior.  A  more  abundant  supply  of  oxygen  may  not  be 
able  to  quicken  its  oxidation  processes ;  a  diminished  chance 
of  acquiring  oxygen  stimulates  them.  ..." 

The  capacity  to  perform  mechanical  work  seems  ap- 
preciably diminished  at  high  elevations;  thus  Zuntz  and 
Schumburg  found  their  ability  to  perform  labor  on  the  top 
of  Monte  Rosa  only  approximately  one-third  of  their  ca- 
pacity in  Berlin.  R.  F.  Fuchs  found  that  in  manual  labor 
the  oxygen  consumption  at  a  level  of  3000  metres  was  dis- 
tinctly, although  not  very  greatly  increased ;  a  very  marked 
increase  became  evident,  however,  at  levels  above  4000 
metres  (although  in  this  matter  the  influence  of  acclima- 
tion and  training  should  be  regarded  as  of  decided  impor- 
tance). It  may  thus  become  appreciable  why  in  case  of 
most  of  the  mountain  climbers  the  mountain  sickness  does 
not  show  itself  below  levels  of  over  4000  metres.66  How- 
ever, it  is  impossible  without  further  investigation  to  under- 

86  A.  Durig,  Wiener  klin.  Wochenschr.,  24,  No.  18. 

88  R.  F.  Fuchs  and  T.  Deimler,  Sitzber.  d.  physik.  med.  Soc.,  Erlangen,  41, 
1909:  Centralbl.  f.  d.  ges.  Biol.,  10,  No.  708. 


608  PHYSIOLOGY  OF  ALPINISM 

stand  why  the  symptoms  of  mountain  sickness,  as  a  rule, 
first  appear  in  the  Ancles  and  in  the  Himalayas  at  much 
greater  heights  than  in  the  European  Alps.  Obviously 
there  must  be,  aside  from  the  rarefaction  of  the  atmosphere, 
quite  a  number  of  other  climatic  factors  which  are  to  be 
taken  into  consideration. 

Nitrogen  Retention. — Besides  the  increased  energy  ex- 
change there  is  manifested  in  elevated  climates  a  notably 
increased  tendency  to  the  retention  of  nitrogen.  This  was 
observed  by  Jaquet  and  by  Durig,  as  well  as  by  G.  v.  Wendt, 
and  must  necessarily  be  regarded  as  a  protein  storage.  The 
observations  of  Durig  upon  the  nitrogen  fractionation  in  the 
urine  showed  no  basis  (contrary  to  A.  Löwy,  who  holds  that 
there  are  faults  of  protein  metabolism  and  an  increase  of 
aminoacids  in  the  urine  in  individuals  sojourning  at  high 
levels)  for  the  idea  that  protein  catabolism  takes  place 
at  all  differently  from  the  process  as  seen  in  the 
lower  plains.  G.  v.  Wendt G7  holds,  as  the  result  of  his  in- 
vestigations, that  the  often  observed  nitrogen  retention  of 
elevated  places  is  not  to  be  explained  as  a  retention  of 
intermediate  compounds,  but  as  connected  with  the  new 
formation  of  living  substance,  particularly  of  the  muscles. 
This  in  no  wise  excludes  the  possibility  that  under  certain 
circumstances  mountain  sickness  may  bring  about  a  toxic 
protein  destruction;  but  we  may  well  regard  an  abnormal 
accumulation  of  fatigue  products  and  not  the  elevated  cli- 
mate itself  as  responsible  for  this,  if  the  author  be  correct 
in  his  conjecture.  Then,  too,  one  should  think  of  the  proc- 
esses of  protein  destruction  and  fatty  change  observed  by 
Zuntz  and  his  pupils  occasionally  in  locations  of  atmospheric 
rarefaction  as  perhaps  connected  with  accumulation  of  an 
excessive  amount  of  lactic  acid  in  the  tissues. 

All  in  all  it  may  be  seen  that  friend  Mephisto  was  not 
very  far  wrong  when  he  answered  Faust  who  was  striving 
to  gain  the  mountain  heights  in  the  rush  of  the  Walpurgis 

67  G.  v.  Wendt,  Skandin.  Arch.  f.  Physiol.,  2)h  247,  1911. 


NITROGEN  RETENTION  609 

night  and  who  said:  "There  many  a  puzzle  must  yield  its 
secret,"  with  the  reply:  "Yet  many  a  puzzle,  too,  is  twin- 
ing its  tangle  there."  Here  in  fact,  as  so  often  in  our 
wandering,  we  find  ourselves  hemmed  in  at  each  step  of  the 
way  by  a  world  of  new  enigmas  for  which  the  future  alone 
will  find  a  solution.  At  all  events,  however,  we  must  ac- 
knowledge our  indebtedness  to  all  those  men  to  whom  the 
thirst  for  knowledge  lent  power  and  energy  to  endure  up 
there  upon  icy  mountain-heights,  with  the  roar  of  storms 
about  them,  for  many  weeks  at  a  stretch,  cold,  loss  of  sleep, 
bodily  discomforts  and  privations  of  every  sort,  and  to 
carry  on  from  day  to  day  with  fixed  purpose  and  with  pa- 
tience their  arduous  and  often  tedious  work  of  investigation. 


39 


CHAPTER  XXV 

FEVER 

In  concluding  our  study  of  metabolism  this  last  chapter 
may  with  propriety  be  devoted  to  the  old  and,  to  the  thought- 
ful physician,  the  daily  recurring  enigma  of  fever,  with  dis- 
cussion of  the  attitude  assumed  by  modern  biochemistry 
toward  this  problem. 

Customarily  such  a  discussion  should  begin  with  a  sober 
presentation  of  a  number  of  definitions  relating  to  the  gen- 
eral concept  of  fever ;  but  this  may  well  be  dispensed  with, 
because  the  author  believes  that  those  whom  he  is  address- 
ing all  realize  what  is  meant  by  the  term,  and  because,  too, 
he  has  never  quite  grasped  why  scientists  so  often  burden 
life  with  insistence  upon  definitions  of  things  whose  real 
nature  they  themselves  are  unable  to  sharply  and  clearly 
depict. 

Total  Metabolism. — The  naive  concept  of  a  man 
"fever  raging  through  his  veins"  approaches  the  idea 
that  "an  internal  fire,"  whose  mildly  tempered  warmth 
under  normal  conditions  protects  the  body  from  chill,  is 
being  fanned  into  a  wild  consuming  flame.  We  may  there- 
fore begin  by  determining  whether  and  to  what  extent  we 
are  justified  in  assuming  in  fever  the  existence  of  an  ex- 
aggeration of  the  vital  combustion  processes.1 

The  idea  of  exaggeration  of  combustion  processes  in 
fever,  which  dominated  the  older  pathology,  was  first  dis- 
turbed by  Senator,  who  was  able  to  point  out  that  in  ex- 
perimentally infected  febrile  animals  it  is  not  necessary 
that  invariably  and  under  all  circumstances  there  be  more 

1  Literature  upon  the  Total  Metabolism  in  Fever :  A.  Jaquet,  Ergebn.  d. 
Physiol.,  2',  548-553,  1903;  C.  Speck,  ibid.,  31-35;  Fr.  Kraus:  Noorden's  Handb. 
d.  Pathol,  d.  Stoffw.,  1,  614-630,  1906;  L.  Krehl,  Pathol.  Physiol.,  5th  Ed., 
482-485,  1907;  A.  Löwy,  Handb.  d.  Biochem.,  -'/'  199-213,  242-243,  1908;  P.  F. 
Richter,  ibid.,  4",  105-112,  1910;  Graham  Lusk,  Ernährung  und  Stoffwechsel, 
2nd  Ed.,  287-293,  1910. 
610 


INFLUENCE  OF  MUSCULAR  ACTIVITY  611 

oxygen  taken  in  and  more  carbonic  acid  given  off  than 
normally.  The  real  condition  of  affairs  was  clearly  in- 
dicated primarily  by  studies  conducted  by  Friedrich  Kraus 
and  A.  Löwy  on  febrile  human  beings  by  employing  the 
Zunz-Geppert  methods.  Their  observations  were  supple- 
mented by  those  of  Riethus,  Steyrer,  Gräfe,2  and  Roily 3  and 
by  the  animal  experiments  of  May  (on  rabbits  infected  with 
swine  erysipelas)  and  of  Stähelin  (on  dogs  inoculated  with 
surra  trypanosomes),  and  by  observations  upon  the  hyper- 
thermia of  heat-puncture.  All  in  all  it  is  now  apparently 
settled  that  there  is  no  basis  for  supposing  that  there  exists 
any  ratio  between  oxidation  increase  and  rise  of  tempera- 
ture, and  that  actually  the  former  may  at  times  not  exist.  In 
general,  however,  metabolism  is  moderately  increased  in 
the  febrile  human  being.  Yet  we  must  of  necessity  inquire 
whether  this  increase  of  metabolism  is  really  inherent  to 
the  nature  of  fever  or  whether  it  may  not  rather  be  the 
result  of  accessory  factors. 

Influence  of  Increased  Muscular  Activity. — As  one  such 
factor  we  must  in  the  first  place  consider  an  increase  of  mus- 
cular activity.  This  may  occur  to  a  marked  degree  in  the 
violent  muscular  contractions  of  a  rigor.  However,  even 
the  extra  effort  manifested  in  the  general  motor  restless- 
ness and  in  the  more  rapid  heart  action  and  respiratory 
movements  must  by  no  means  be  undervalued.  "If  one 
excludes  the  rise  in  temperature  occasioned  by  muscular 
movements,"  says  Krehl,4  "which  may  be  manifested  even 
without  the  existence  of  fever  and  therefore  properly  is  not 
to  be  regarded  as  belonging  to  it,  the  heat  production  during 
fever  would  be  found  to  range  in  the  proportion  110-160 : 
100 ;  figures  like  120-130 :  100  may  be  regarded  as  average.5 

2E.  Gräfe  (Med.  Clinic,  Heidelberg),  Deutsch.  Arch.  f.  klin.  Med.,  101,  209, 
1910. 

3F.  Roily  (Med.  Clinic,  Leipzig),  Deutsch.  Arch.  f.  klin.  Med.,  103,  93, 
1911. 

4  Krehl,  1.  c,  p.  483. 

5  Cf.  also  E.  Gräfe  (Med.  Clinic,  Heidelberg),  Deutsch.  Arch.  f.  klin.  Med., 
101,  209,  1910. 


612  FEVER 

These  are  but  trifling  accessions,  if  we  recall  that  Rubner 
was  able  to  raise  the  heat  production  to  160 :  100  in  the  dog 
merely  by  overfeeding  with  protein,  and  that  they  can  be 
multiplied  by  severe  muscular  movements." 

Rise  of  Reaction  Velocity  of  Metabolic  Processes  with 
the  Temperature. — A  second  important  element  must  be 
recognized  in  the  rule  governing  chemical  processes  of 
every  sort,  whether  they  take  place  within  or  outside  the 
body,  that  every  rise  of  temperature  is  associated  with  an 
increase  in  the  velocity  of  reaction.  Indeed,  according  to 
Vant'HofT,  for  a  rise  of  ten  degrees  of  temperature  the 
rapidity  of  reaction  may  be  observed  to  be  doubled  or 
trebled.  This  "reaction-velocity-temperature"  rule  (EVT- 
rule  or  RGT-rule,  as  Kanitz  calls  it)6  holds  in  a  very  great 
number  of  biological  processes.  Thus,  for  instance,  it  has 
been  proved  in  the  assimilation  and  output  of  carbonic  acid 
by  plants,  in  the  budding  of  yeast,  cell-division  of  fertilized 
frog-ova  and  sea-urchin  ova,  the  frequence  of  action  of  the 
pulsating  vacuole  in  infusoria,  the  heart  beat  in  cold-blooded 
and  warm-blooded  animals,  in  the  rhythmic  movements  of 
the  frog's  oesophagus  and  the  small  intestine,  and  in  the 
transmission  of  stimulation  processes  in  nerves.7  Obviously 
the  rule  is  effective  only  up  to  that  limit  of  temperature 
(about  40°  C.)  within  which  beginning  protein  coagulation 
does  not  give  rise  to  disturbing  changes. 

The  dependence  of  the  gas  metabolism  upon  temperature 
was  recognized  some  time  since  by  Pflüger  in  case  of  cold- 
blooded animals.  In  the  warm-blooded  animal  as  well,  in 
which  normally  the  influence  of  the  surrounding  tempera- 
ture is  masked  by  regulatory  processes,  the  same  feature 
is  manifested,  provided  these  are  partly  excluded  by  section 
of  the  cord  or  by  curare  poisoning.  In  fact,  as  previously 
stated,  the  minimal  metabolism  in  inhabitants  of  the  tropics 

•Cf.  A.  Kanitz,  R.  O.  Herzog,  R.  Abegg,  Zeitschr.  f.  Elektrochem.,  1905- 
1907. 

'Literature:  K.  Spiro,  Handb.  d.  Biochem.,  2',  4,  1910. 


INCREASE  OF  REACTION  VELOCITY  613 

is  neither  greater  nor  less  than  that  in  inhabitants  of  the 
temperate  zones,8  yet  their  body  temperature  is  also  con- 
stant; bnt  from  the  effects  of  hot  baths  (including  hot  air 
baths  and  radiant  light  baths)  by  which  the  temperature  of 
the  body  is  raised  to  38-39.5°  C,  a  very  distinct  and  some- 
times a  very  important  increase  of  metabolism  is  attained.9 
In  an  individual  suffering  from  ichthyosis  (fish-scale  dis- 
ease), in  which  affection  the  output  of  water  through  the 
sweat  glands  and  in  connection  therewith  the  heat  regu- 
lation as  well,  are  apparently  decidedly  diminished  by 
simple  sojourn  in  a  well-heated  room  (in  spite  of  the  fact 
that  the  body  temperature  never  exceeded  39°  C.)  the 
exchange  was  increased  to  double  the  normal. 

It  therefore  seems  quite  plausible  that  if  the  body  tem- 
perature is  raised  by  any  single  cause  this  temperature 
accession  in  itself  drives  the  exchange  up.  Friedrich 
Kraus  10  says  definitely  in  this  connection  that,  if  from  the 
gross  amount  of  oxygen  requirement  found  in  human  beings 
with  fever  there  be  subtracted  the  amount  due  to  grossly 
visible  muscular  movements  and  besides  the  excess  due  to 
the  increased  fever  heat  itself,  a  neat  amount,  not  very 
important  in  the  average,  will  remain.  Increase  in  the  com- 
bustion processes  can  be  safely  said  not  to  be  the  cause  of 
fever ;  and  in  fact  one  would  hesitate  in  a  given  case  to  class 
this  as  one  of  the  characteristic  features  of  fever,  and  would 
be  forced  to  acknowledge  that  excessive  muscular  exertion, 
in  spite  of  the  fact  that  it  raises  the  gas  exchange  to  a 
multiple  of  the  normal,  leaves  the  individual  temperature 
of  the  healthy  body  at  the  normal  level. 

8  According  to  Eykmann,  Aron,  and  others. 

9  Observations  of  W.  Winternitz  and  O.  Pospischil,  H.  Winternitz,  H. 
Salomon,  Linser  and  Schmidt:  Literature:  A.  Löwy,  1.  c,  pp.  212-214.  Accord- 
ing to  recent  experiments  of  H.  Murschhauser  (Schlossmann's  Clinic,  Düssel- 
dorf), Zeitschr.  f.  physiol.  Chem.,  75,  301,  1912,  a  long-continued  exposure  to 
external  temperatures  of  +  5°  in  the  first  place  and  of  +  35°  in  the  second 
place  need  not  give  rise  to  any  important  change  in  the  metabolism  provided 
the  body  temperature  is  not  altered.  Cf.  also  J.  Ignatius,  L.  Lund  and  0.  Wärri 
(Helsingfors),  Skandin.  Arch.,  20,  226,  1909. 

10  F.  Kraus,  1.  c,  p.  628. 


614  FEVER 

Frugality  of  the  Body  in  Chronic  Febrile  Conditions. — 
It  would  be  altogether  a  mistake  to  assume,  for  the  rest, 
that  the  organism  in  a  state  of  fever  deals  with  its  material 
in  any  especially  extravagant  manner.  In  fact  precisely  the 
opposite  is  apparently  true.  At  least  in  the  later  part  of 
the  course  of  very  slowly  declining  cases  of  typhoid  fever 
and,  too,  in  pulmonary  phthisis,  C.  von  Noorden  repeatedly 
observed  that  the  body  cells  of  human  beings  in  protracted 
fever  are  able  to  functionate  very  economically  on  a  con- 
sumption of  20  to  25  calories  pro  kilogram  of  body  weight. 
This  may  explain  how  chronic  febrile  subjects  after  having 
at  first  lost  rapidly  in  body  weight,  later,  in  spite  of  a 
notably  lower  ingestion  of  food,  are  able  to  maintain  for  a 
long  period  their  body  weight  at  almost  constant  level.11 
It  may  be  added,  too,  that  Montouri,12  who  transferred  the 
blood  of  an  experimentally  overheated  dog  into  the  jugular 
vein  of  a  second  dog,  thought  that  he  observed  that  it  con- 
tained substances  which  inhibited  heat  production  in  the 
normal  organism.  However,  many  objections  are  possible 
against  this  type  of  experiments. 

Respiratory  Quotient. — Upon  the  bearing  of  the  respira- 
tory quotient  in  fever  the  views  of  authorities  are  some- 
what contradictory,  many  being  of  the  opinion  that  it  is  not 
lower  than  in  the  normal  state,13  while  others  hold  that  a 
reduction  exists.14  However,  it  seems  scarcely  likely  to  go 
lower  than  0.7. 15  We  are  clearly  justified  in  ranking  fever 
metabolism  along  with  inanition  metabolism,  in  which  (ac- 
cording to  Zuntz)  the  quotient  likewise  presents  a  lower 
value;  but  in  both  cases  the  economy  endeavors  to  carry 
energy  demands  continuously  put  upon  it  principally  at 
the  expense  of  its  fat  supply. 

a  Cf.  Fr.  Kraus,  1.  c,  p.  629. 

UA.  Montouri,  Richerche  biotermiche,  Giannini,  Naples,  1904;  cited  in 
Centralbl.  f.  Physiol.,  19,  285,  1905. 

13  Cf.  Roily,  Deutsch.  Arch.  f.  klin.  Med.,  103,  93,  1911,  and  earlier  papers. 

14  P.  F.  Richter,  1.  c.  pp.  109-111. 

15  E.  Gräfe  (Med.  Clinic,  Heidelberg),  Deutsch.  Arch.  f.  klin.  Med.,  101, 
209,  1910. 


DECREASED  HEAT  ELIMINATION  615 

Reduction  Power  of  the  Tissues. — That  but  little  is  to 
be  expected  from  attempts  to  estimate  the  reduction  ca- 
pacity of  the  tissues  of  febrile  subjects  by  the  decoloriza- 
tion  of  methylene  blue  and  similar  methods,  is  indicated 
from  what  has  been  above  said  in  reference  to  the  char- 
acter of  such  processes.  One  author  16  observed  in  experi- 
mentally-induced fever  an  increased,  while  another  1T  ob- 
served a  reduced  reduction  power.  The  author  is  inclined  to 
look  upon  the  whole  subject  as  a  rather  unfortunate  one, 
which  leads  only  to  fictitious  results,  which  cannot  give  any 
information  as  to  vital  processes. 

Decreased  Heat  Elimination. — Krehl  and  Soetbeer 18 
found  that  in  frogs  which  they  had  inoculated  with  patho- 
genic microorganisms  the  production  of  heat  increased  with 
the  fever ;  they  hold  ' '  that  in  animals  in  which  the  influence 
of  the  nervous  system  upon  heat  production  in  muscle  is 
thoroughly  excluded,  a  distinct  rise  in  heat  production  takes 
place  from  the  influence  of  infection. ' '  We  would  of  neces- 
sity from  this  assume  that  at  times  in  fever  the  production 
of  heat  can  be  increased.  Yet  Krehl  himself  on  the  ground 
of  his  extensive  studies  conducted  in  association  with 
Matthes,19  arrived  at  the  opinion  that,  no  matter  whether 
the  oxidations  may  or  may  not  be  raised  in  the  body  in 
fever,  the  chief  basis  of  temperature  accession  is  not  to  be 
found  in  an  increased  heat  production  but  in  a  decreased 
heat  elimination. 

Modern  experimental  results  therefore  bring  us  to  the 
same  conclusion  to  which  Traube  from  his  own  celebrated 
studies  came,  regarding  the  essential  cause  of  fever  as 
referable  not  to  the  increased  production  of  heat  but  to  a 
disturbance  of  heat  elimination.  He  attributed  fever  to  a 
spasmodic  constriction  of  peripheral  vessels  interfering 
with  the  normal  outlet  of  heat  from  the  body  surface.    It 

16  C.  A.  Herter,  Amer.  Jour,  of  Physiol.,  12,  457,  1904. 

"V.  Schlüpfer,  Zeitschr.  f.  exper.  Pathol.,  8,  181,  1911. 

18  L.  Krehl  and  F.  Soetbeer,  Arch.  f.  exper.  Pathol.,  40,  275,  1897. 

"  L.  Krehl  and  M.  Matthes,  Arch.  f.  exper.  Pathol.,  38,  284,  1897. 


616  FEVER 

should  be  recalled  in  this  connection  that  if  a  healthy  man 
steps  into  a  cold  bath,  a  contraction  of  the  peripheral  ar- 
teries may  result  in  a  transitory  rise  in  the  body  tempera- 
ture ;  after  leaving  the  bath  the  blood  flows  in  full  propor- 
tion to  the  surface  and  the  skin  reddens.  In  chills  the  skin, 
as  the  result  of  vascular  contraction,  looks  bloodless,  and  in 
response  to  stimulation  of  the  cutaneous  nerve  endings  which 
are  sensitive  to  cold,  the  production  of  heat  in  the  muscles 
increases  reflexly.  Replacement  of  the  stimulus  from  cold 
by  a  warm  covering  about  the  body  may  in  conformity 
reduce  the  production  of  heat.20 

Protein  Destruction. — Proceeding  with  consideration  of 
the  metabolic  processes  in  fever,  we  come  first  to  the  problem 
of  febrile  protein  destruction.21 

Undoubtedly  fever  may  be  associated  with  a  marked 
protein  disintegration  which  manifests  itself  by  an  in- 
creased urea  elimination.  Frequently  this  latter  feature 
fails  to  put  in  appearance  until  after  the  fever  has  already 
declined.  Thus,  for  example,  Naunyn  observed  in  a  case  of 
typhus  exanthematicus  on  the  tenth  day  of  the  febrile  course 
a  urea  elimination  of  only  ten  grams,  but  on  the  fourteenth 
day,  with  the  temperature  down  to  normal,  the  urea  excre- 
tion reached  ninety  grams.  It  is  not  an  easy  matter  to 
formulate  a  proper  interpretation  of  an l '  epicritical  nitrogen 
elimination"  of  this  sort.  It  cannot  be  held  that  the  elim- 
ination of  already  formed  urea  has  been  retarded ;  Naunyn 
has  convinced  himself  that  urea  accumulation  does  not  take 
place  in  the  tissues  of  febrile  individuals,  and  that  the  body 
in  the  state  of  fever  can  readily  excrete  urea,  which  is  itself 
very  diuretic  when  experimentally  introduced  into  the  cir- 
culation.   It  seems  much  more  plausible  on  the  other  hand 

20  Cf.  Graham  Lusk,  1.  c,  pp.  288-292. 

21  Literature  upon  Protein  Metabolism  in  Fever :  C.  Speck.  Ergebn.  d. 
Physiol.,  2",  27-30,  1903 ;  F.  Kraus,  Noorden's  Handb.  d.  Pathol,  d.  Stoffw.,  1, 
590-610,  1906;  L.  Krehl,  Pathologische  Physiologie,  5th  Ed.,  491-495,  1907; 
Graham  Lusk,  Ernährung  und  Stoffwechsel,  285-288,  294-302,  1910;  P.  F. 
Richter,  Handb.  d.  Biochem.,  .'/,  112-119,  1910. 


PROTEIN  DESTRUCTION  617 

that  the  febrile  affection  may  induce  some  degenerative 
change  in  organic  structures  (as  may  be  recognized  morpho- 
logically in  the  parenchymatous  degeneration  of  glandular 
tissues  and  the  hyaline  coagulation  of  muscles),  and  that  a 
gradual  elimination  of  tissue  constituents  which  have  been 
rendered  useless  is  responsible  for  the  epicritical  urea  ex- 
cretion. The  destruction  of  protein  may  sometimes  attain 
an  extremely  high  grade  in  febrile  affections.  Thus,  for 
example,  according  to  Friedrich  Kraus,22  it  is  not  a  very 
rare  occurrence  in  pneumonia  to  encounter  an  increase  of 
nitrogen  elimination  corresponding  to  as  much  as  half  a 
kilogram  of  muscle  tissue  per  diem.  Friedrich  Müller  has 
recorded  a  case  of  typhoid  fever  in  which  the  patient  lost  in 
the  course  of  a  single  week  an  amount  of  nitrogen  which 
would  correspond  with  a  daily  destruction  of  360  grams  of 
muscle. 

The  question  next  arises  how  this  increased  protein  de- 
composition is  to  be  interpreted.  The  first  thought  that  the 
hyperthermia  itself  is  the  immediate  cause  of  this  destruc- 
tion must  be  rejected.  Naunyn  succeeded  in  superheating 
rabbits  experimentally  for  periods  of  two  weeks  so  that 
their  body  temperature  exceeded  41°  C.  as  an  average,  and 
yet  there  was  not  the  least  trace  of  parenchymatous  or 
fatty  degeueration  appreciable  in  their  organs.  In  man, 
according  to  Linser  and  Schmidt  the  status  of  experimental 
heating  seems  to  be  that  as  long  as  the  temperature  remains 
below  39°  C.  no  increase  of  nitrogen  elimination  is  to  be 
noted,  but  that  it  becomes  apparent  as  soon  as  the  temper- 
ature exceeds  40°  C.  But  the  protein  decomposition  does 
not  bear  any  fixed  relation  with  the  height  of  the  fever. 
Senator  long  since  made  observation  of  the  fact  that  in 
malaria  if  the  temperature  be  artificially  kept  low  by  qui- 
nine, there  is  not  necessarily  any  diminution  of  the  protein 
destruction.  Deucher  saw  the  reverse,  that  in  typhoid  fever 
various  antipyretics  may  lower  the  loss  of  nitrogen  inde- 

21 L.  c,  p.  506. 


618  FEVER 

pendently  of  any  lowering  of  the  temperature.23  In  sepsis 
in  spite  of  a  low  grade  of  fever  a  marked  protein  disin- 
tegration may  be  noticeable.  The  hyperthermia  alone  is 
therefore  not  sufficient  to  explain  the  exaggerated  nitrogen 
elimination  in  fever  to  say  the  least. 

The  resorption  of  inflammatory  exudates  is  no  better 
adapted  to  furnish  a  complete  explanation. 

A  very  important  factor  unquestionably  is  to  be  recog- 
nized in  the  toxogenic  protein  decomposition  occurring  in 
infectious  diseases,  associated  with  the  development  of 
lesions  of  the  tissue  cells  from  disease  poisons.  But  even 
this  explanation  is  not  sufficient  in  all  cases;  thus,  for  ex- 
ample, it  does  not  hold  for  the  protein  destruction  which 
accompanies  the  heat  puncture  (puncture  into  the  corpus 
striatum).  It  is  obvious  that  we  are  not  to  confuse  an 
increased  breakdown  of  protein  with  an  increase  of  oxida- 
tion, as  has  been  sometimes  done.  In  fact  even  a  reduction 
in  the  processes  of  oxidation  from  lack  of  oxygen  may  lead 
to  an  increased  protein  destruction. 

Inhibition  of  Febrile  Protein  Destruction  by  Increasing 
Carbohydrate  Food. — Many  authors  are  inclined  to  em- 
phasize the  feature  of  inanition  in  febrile  protein  destruc- 
tion. Thus  F.  Voit  found  that  the  protein  breakdown  after 
superheating  may  be  decidedly  repressed  by  free  exhibition 
of  non-nitrogenous  food,  and  May  was  able  to  lower  the 
nitrogen  elimination  even  more  decidedly  in  febrile  animals 
by  injecting  solutions  of  sugar  than  in  starving  animals, 
v.  Leyden  and  Klemperer  24  have  attempted  to  do  away 
with  tissue  destruction  in  febrile  human  beings  by  full  nour- 
ishment, and  have  called  attention  in  this  connection  to  the 
fact  that  two  liters  of  milk  with  an  additional  ten  per  cent, 
of  milk  sugar,  with  a  calory  equivalent  of  more  than  2000, 
are  sufficient  to  approximately  cover  the  daily  nutritive  re- 

23  P.  Deucher  (Sahli's  Clinic,  Berne),  Zeitschr.  f.  klin.  Med.,  57,  429,  1905. 
21  v.  Leyden  and  Klemperer,  v.  Leyden's  Handb.  d.  Ernährung,  2,  345,  1904. 


ELIMINATION  OF  METABOLIC  END-PRODUCTS    619 

quirement  of  a  bed-fast  human  being.  Schaffer  25  was  able 
to  maintain  a  case  of  typhoid  fever  on  a  diet  low  in  protein, 
but  rich  in  carbohydrate  (consisting  of  milk,  milk-sugar, 
cream,  eggs  and  arrowroot)  at  approximate  nitrogen  bal- 
ance. Similar  attempts  have  recently  been  carried  out  at 
the  Heidelberg  medical  clinic  by  Gräfe,26  who  obtained  prac- 
tical nitrogen  balance  in  febrile  human  subjects  by  an  ex- 
hibition of  food  of  fifty  calories  per  kilogram ;  as  the  result 
of  which  he  regards  the  assumption  of  a  toxogenic  protein 
decomposition  as  superfluous.  There  is  thus  no  doubt  of 
the  fact  that  destruction  of  protein  in  fever  can  be  materially 
lessened  by  administration  of  judiciously  selected  food. 

We  may  perhaps  approach  most  nearly  to  the  truth  by 
holding  that  the  destruction  of  protein  in  fever  is  caused  by 
a  combination  of  influences  from  the  above-mentioned  fac- 
tors, of  which  now  one,  now  another,  may  come  to  be  domi- 
nant according  to  circumstances. 

Elimination  of  Nitrogenous  Metabolic  End-Products. — 
In  view  of  the  extensive  destruction  of  protein  which  may 
take  place  in  fever  it  is  not  at  all  remarkable  that  the  elim- 
ination of  nitrogenous  end-products  of  metabolism  may 
present  certain  abnormalities.27  According  to  statements 
already  made  in  reference  to  "endogenous"  cellular  me- 
tabolism it  can  be  readily  appreciated  how  in  fever  some- 
times a  decided  increase  in  the  output  of  uric  acid  and  of 
Creatinin  (or  the  total  creatin  -f-  Creatinin )2S  has  come  to 
be  observed  in  connection  with  the  increased  protein  decom- 
position, and  how  at  times  certain  residua  of  protein  me- 
tabolism (or  products  of  incomplete  protein  decomposition) 
may  be  met  in  increased  quantity  in  the  urine.     The  fre- 

»P,  A.  Schaffer  (Cornell  Med.  College,  New  York),  Jour,  of  Amer.  Med. 
Assoc.,  51,  974,  1908. 

*E.  Gräfe  (Med.  Clinic,  Heidelberg),  Vortr.  auf  d.  Karlsruher  Natur- 
forscher Vers.,  1911,  cited  in  Centralbl.  f.  d.  Ges.  Biol.,  13,  No.  932. 

HCf.  Literature,  P.  F.  Richter,  1.  c,  pp.  119-123. 

2'Cf.  also  V.  C.  Myers  and  G.  O.  Volovic,  Amer.  Jour,  of  Physiol.,  29, 
Proc.  Amer.  Physiol.  Soc.,  XVIII,  1912. 


620  FEVER 

quent  occurrence  of  albumoses  in  the  urine  of  febrile  indi- 
viduals observed  by  Krehl  and  Matthes  may  be  classed  here ; 
as,  too,  the  much  discussed  shifting  of  the  relation  of  the 
carbon  to  the  nitrogen  in  the  urine.29  It  would  be  scarcely 
wrong  to  assume  that  in  the  latter  group  the  oxyproteic 
acids  are  certainly  included,  that  is,  high  molecular  products 
of  protein  cleavage  which,  however,  no  longer  yield  typical 
proteid  reactions.  Uncertainty  on  this  point  is  due  especi- 
ally to  the  fact  that  we  unfortunately,  up  to  the  present 
time,  have  no  exact  method  of  determining  the  oxyproteic 
acids  in  the  urine.  In  this  connection  the  diazoreaction  in 
febrile  urine  comes  suggestively  in  a  new  light.  (This  is 
met  with  regularity  in  typhoid  fever  and  typhus  exanthe- 
maticus,  in  advanced  phthisis,  measles,  as  well  as  in  puer- 
peral fever  and  septic  processes  of  various  kinds,  in  severe 
cases  of  pneumonia,  scarlet  fever  and  erysipelas.)30  There 
is  at  present  every  reason  for  assuming  (vide  supra,  p.  139) 
that  the  diazoreaction  is  connected  with  one  of  the  oxy- 
proteic acids,  and  probably  with  one  which  owes  its  chromo- 
genic  character  to  a  contained  cyclical  group  coming  from 
the  protein  molecule  (apparently  histidin),  and  which  may 
be  regarded  as  the  mother  substance  of  the  normal  yellow 
urinary  coloring  matter,  urochrome. 

Acidosis  and  Fat  Destruction. — Sometimes  in  examining 
the  urine  of  febrile  cases  the  amount  of  ammonia  is  found 
somewhat  increased  in  proportion  to  urea.  This  is  a  mani- 
festation of  an  acidosis  of  moderate  degree,  to  which  atten- 
tion was  first  directed  by  v.  Jaksch  and  to  which  since  then 
considerable  study  has  been  devoted.31  It  by  no  means 
attains  the  grade  met  in  diabetes.  And  in  the  blood,  as 
P.  Frankel  determined  in  the  laboratory  of  Friedrich  Kraus 
by  the  aid  of  the  method  of  electric  concentration  chains,  it 
is  not  possible  to  recognize  any  change  of  the  hydrogen  ion 

29  A.  Löwy,  Scholz,  May,  Roily,  Magnus-Alsleben,  and  others. 
3U  Cf.  F.  Kraus,  1.  c,  pp.  660-662. 

SlCf.  Literature:  F.  Kraus,  1.  c,  pp.  656-660,  1906;  P.  F.  Richter,  1.  c, 
pp.  123-125,  133-136,  1910. 


CARBOHYDRATE  METABOLISM  IN  FEVER         621 

acidity ;  but  it  must  be  remembered  that  the  body  has  avail- 
able means  to  keep  its  juices  neutral  as  long  as  the  excess 
of  acid  does  not  reach  too  high  a  degree.  According  to  the 
present  status  of  our  knowledge  we  may  refer  the  increased 
production  of  acetone  bodies  (ß-oxj butyric  acid,  diacetic 
acid,  acetone)  in  fever  to  a  heightened  fat  destruction,  which 
becomes  so  manifest  from  the  wasting  occasioned  by  pro- 
longed fever  that  any  further  proof  seems  superfluous. 
Blumenthal  noted  in  streptococcus  infections  a  higher  grade 
acetonuria  than  in  other  febrile  affections,  and  Bottazzi  saw 
in  diphtheria  the  curve  of  the  acetone  bodies  fall  under  the 
influence  of  the  curative  serum;  which  facts  will  probably, 
in  the  writer's  opinion,  be  brought  into  relation  with  varia- 
tions in  the  intensity  of  fat  destruction. 

Relation  of  Carbohydrate  Metabolism  to  Fever. — A  great 
number  of  investigations  have  been  directed  to  the  relations 
of  carbohydrate  metabolism  to  fever.  Although  the  studies 
in  relation  to  the  amount  of  sugar  in  the  blood  of  animals 
exposed  to  cold,  to  heat  and  of  febrile  animals  do  not  admit 
of  any  simple  interpretation  as  far  as  the  author  sees,32  there 
is  not  the  least  reason  to  doubt  that  destruction  of  carbo- 
hydrates in  the  tissues,  and  especially  in  the  liver,  is  in- 
volved to  a  very  important  degree  in  the  processes  of  heat 
production  in  the  body,  and  (as  inter  alia  is  indicated  from 
observations  by  Cavazzani)  is  subject  to  regulatory  influ- 
ences from  the  nervous  system.  This  is  illustrated  in  a  very 
suggestive  manner  by  observations  by  Dubois  and  also  by 
E.  Weinland,33  showing  that  in  the  niarmot  as  it  wakes  from 
its  hibernation  the  glycogen  supply  falls  within  a  few  hours 
to  half  its  quantity,  and  that  the  temperature  coincidently 
rises.    Hirsch  and  Roily  have  suggested  that  glycogen-free 

"G.  Embden,  H.  Lüthje  and  E.  Liefmann,  Hofmeister's  Beitr.,  10,  2(35, 
1907;  H.  Senator,  Zeitschr.  f.  klin.  Med.,  67,  253,  1908;  R.  Lepine  and  Bouhid, 
C.  R.  Soc.  de  Biol.,  69,  379,  1910;  A.  Hollinger  (Liithje's  Clinic,  Frankfurt 
a.  M.),  Deutsch.  Arch.  f.  klin.  Med.,  92,  217,  1908. 

33  E.  Weinland  and  M.  Riehl  (Physiol.  Instit.,  Munich),  Zeitschr.  f.  Biol., 
50,  75,  1908. 


622  FEVER 

animals  are  not  exempt  as  a  matter  of  fact  from  infectious 
fever,  but  are  exempt  from  the  hyperthermia  of  the  heat 
puncture.  But  as  meanwhile  it  appears  from  studies  of 
Senator  and  P.  F.  Richter  that,  even  in  animals  rendered 
practically  free  of  glycogen  by  a  combination  of  starvation 
and  strychnine  poisoning,  the  heat  puncture  remains  effec- 
tive although  in  a  lessened  degree,  there  need  be  no  occasion 
for  entering  into  the  interpretations  which  have  been  pro- 
posed for  the  former  experiments.  It  is  safe  to  say  that 
there  is  no  form  of  hyperthermia  which  is  invariably  con- 
nected with  an  increased  accumulation  of  glycogen  in  the 
tissues.34 

Changes  in  the  Constitution  of  the  Blood  Plasma. — A 
characteristic  alteration  of  the  blood  has  been  persistently 
sought  for.  There  are  two  features,  as  far  as  the  author 
sees,  which  have  been  brought  out :  an  increase  of  globulin 
and  an  increase  of  fibrinogen  in  proportion  to  the  other 
proteins  of  the  blood  (cf.  Vol.  I  of  this  series,  pp.  194  and 
244,  Chemistry  of  the  Tissues).  The  increase  of  globulin, 
which  has  been  observed  by  a  large  number  of  authorities,35 
is  a  feature  of  inanition  conditions  of  various  kinds ;  while 
increase  of  fibrinogen,  according  to  T.  Pfeiffer,  is  apt  to  be 
met  especially  in  infections  due  to  pneumococci  and  strep- 
tococci. It  apparently  goes  hand  in  hand,  according  to  P.  T. 
Müller,  with  a  fibrinogen  enrichment  of  lymphadenoid  tis- 
sues, especially  the  bone  marrow.  Of  course  the  idea  is 
suggested  that  the  "hyperinosis,"  or  increase  in  the  amount 
of  fibrinogen  in  the  blood,  which  occasions  the  ' '  crusta  phlo- 
gista"  (that  well-known  coagulation  phenomenon  of  the  old 
physicians),  may  be  connected  with  an  increased  produc- 
tion of  fibrinogen  in  the  bone  marrow. 

34  Literature  upon  the  Relation  of  Carbohydrate  Metabolism  to  Fever : 
F.  Kraus,  1.  c,  pp.  630-634,  1906;  A.  Magnus-Levy,  Handb.  d.  Biochem.,  4', 
363-364,  1909;  I.  Wohlgemuth,  ibid.,  8',  173-174,  1910;  P.  F.  Richter,  ibid., 
4",  125-128,  1910. 

35  Joachim,  Langstein  and  Mayer,  Moll,  Cavazzuoli;  Literature:  F.  Kraus, 
1.  c,  pp.  CI  1-613,  and  P.  F.  Richter,  1.  c,  p.  137. 


WATER  ECONOMY  IN  FEVER  C23 

Water  Economy  in  Fever. — Since  the  investigations  of 
Leyden  the  assumption  of  a  water  retention  in  fever  has 
played  an  important  part  in  the  pathology  of  the  latter  con- 
dition. However,  there  is  certainly  nothing  in  such  water 
retention  that  is  really  characteristic  of  fever.  Schwenken- 
becher  and  Inagaki36  showed  in  Krehl's  clinic  that  in 
typhoid  patients  the  loss  of  water  may  exceed  the  average 
intake.  However,  in  many  of  the  infectious  diseases  a  cer- 
tain tendency  to  water  retention  seems  to  prevail.  Studies 
conducted  in  Rudolf  Gottlieb's  laboratory  in  reference  to 
the  importance  of  the  tissues  as  water  depots,  have  indicated 
that  when  physiological  salt  solution  is  introduced  intraven- 
ously in  dogs  all  the  soft  parts  take  up  water,  even  to  a 
higher  degree  than  does  the  blood.  The  highest  impor- 
tance as  a  place  for  storage  of  water  must  be  attributed 
to  the  muscles ;  they  take  up  about  two-thirds  of  the  water 
deposited  in  the  tissues,  that  is,  more  than  would  corre- 
spond to  their  percentage  proportion  in  the  body.  About 
one-sixth  of  the  water  taken  in  is  in  the  skin,  and  but  very 
little  in  the  intestines.37  The  water  retained  in  fever  is  thus 
to  be  sought,  not  in  the  blood,  but  in  the  tissues.  Schwenken-- 
becher  and  Inagaki 38  found  in  their  studies  upon  the  amount 
of  water  in  the  tissues  of  individuals  who  died  from  febrile 
affections  that  it  was  relatively  increased  in  proportion  to 
their  dry  substance.  Krehl39  says:  "It  is  not  easy  to  say 
at  once  why  this  relative  excess  of  water  in  the  body  is  not 
adjusted,  although  at  other  times  even  a  large  intake  of 
fluid  (three  or  four  liters,  or  more)  is  at  once  eliminated. 
This  much  only  is  to  be  suspected,  namely,  that  the  increase 
in  humidity  for  the  most  part  involves  particularly  the  tis- 
sue elements  and  the  excess  of  water  does  not  enter  the 

36  Schwenkenbecher  and  Inagaki   (Krehl's  Med.  Clinic,  Strassburg),  Arch. 
f.  exper.  Pathol.,  51,  168,  1906. 

37  W.  Engels   (Lab.  of  R.  Gottlieb,  Heidelberg),  Arch.  f.  exper.  Pathol..  51, 
346,  1904. 

38  Schwenkenbecher  and  Inagaki   (Krehl's  Med.  Clinic,  Strassburg),  Arch, 
f.  exper.  Pathol.,  55,  203,  1906. 

39  L.  Krehl,  Pathol.  Physiologie,  5th  Ed.,  p.  509,  1907. 


624  FEVER 

lymph  and  blood  circulation.  There  is  thus  developed  an 
increase  in  the  capacity  of  the  cells  for  imbibition  under 
the  influence  of  many  of  the  infectious  diseases."  This 
feature  seems  at  any  rate  to  be  more  important  than  other 
factors  which  have  been  held  responsible  for  the  retention 
of  water,  as,  for  example,  a  decrease  of  output  (or  at  least 
a  failure  of  increase  of  output)  of  water  by  the  skin40 
(although  it  is  recognized  that  at  the  subsidence  of  fever 
the  perspiratory  secretion  is  usually  increased  in  propor- 
tion to  the  fall  in  temperature).41  Neither  the  experiments 
of  Stähelin  on  febrile  animals  nor  those  of  Carpenter  and 
Benedict  on  human  beings  favor  the  idea  of  a  suppression 
of  the  cutaneous  output  of  water.42  There  is  just  as  little 
conviction  in  the  attempt  to  explain  the  phenomenon  by  the 
view  that  fever  induces  a  retention  of  sodium  chloride  (vide 
infra)  because  of  renal  inefficiency  and  that  this  in  turn  leads 
to  the  water  retention. 

Swelling  of  Cellular  Protoplasm. — It  would  seem  that 
the  most  important  item  which  is  to  be  considered  here  has 
been  heretofore  overlooked,  an  increased  acidification  of 
the  tissues  from  the  accumulation  of  ß-oxybutyric  acid  above 
discussed  (vide  supra,  p.  436).  Perhaps,  too,  an  accumula- 
tion of  lactic  acid  may  be  considered.  From  what  we  have 
learned  experimentally  in  regard  to  the  relation  of  the 
formation  of  acids  in  the  tissues  to  the  occurrence  of  swell- 
ing of  the  latter  (Vol.  I  of  this  series,  pp.  255-257,  Chem- 
istry of  the  Tissues)  it  would  appear  quite  probable  that  an 
increased  fixation  of  water  in  the  tissues  of  febrile  subjects 

40  Cf.  G.  Lang  (Med.  Clinic,  Tübingen),  Deutsch.  Arch.  f.  klin.  Med.,  79, 
343,  1903. 

41  Schwenkenbecher  and  Inagaki  (Krehl's  Med.  Clinic,  Strassburg),  Arch, 
f.  exper.  Pathol.,  58,  365,  1905.  The  output  of  moisture  through  the  skin  is 
in  general  approximately  in  proportion  to  the  temperature  and  to  the  incom- 
pleteness of  saturation  of  the  atmosphere  and  is  at  once  increased  by  moderate 
muscular  effort.  Cf.  A.  J.  Kalmann  (Zoth's  Lab.,  Gratz),  Pfhiger's  Arch.,  112, 
561,  1906;  E.  Heilner  (Physiol.  Instit.,  Munich),  Zeitschr.  f.  Biol.,  !t9,  373, 
1907. 

42 Cf.  Literature:  F.  Kraus,  1.  c,  pp.  635-638,  and  P.  F.  Richter,  1.  c, 
pp.   130-131. 


CHLORINE  RETENTION  625 

might  be  referred  primarily  to  this  as  a  cause.  Although 
Max  Herz  43  has  proposed  in  this  connection  the  hypothesis 
that  a  swelling  of  the  cellular  protoplasm  may  be  the  source 
of  the  heat  of  fever,  the  author  is  disposed  to  regard  this 
view  as  a  reversal  of  cause  and  effect;  and  in  accordance 
with  this  belief  it  may  be  suggested,  therefore,  not  that 
fever  is  occasioned  by  a  protoplasmic  swelling,  but  that  on 
the  contrary,  fever,  by  occasioning  an  accumulation  of  acids 
in  the  tissues,  may  sometimes  lead  to  an  increased  swelling 
of  the  latter. 

Chlorine  Retention. — In  connection  with  the  retention  of 
water  in  the  economy  of  febrile  subjects  it  is  necessary  to 
consider  also  the  retention  of  chlorine.  It  is  a  fact  well 
known  for  a  very  long  time  that  at  the  height  of  many 
febrile  diseases  (especially  pneumonia,  typhoid  fever  and 
scarlet  fever,  but  not  malaria)  that  the  urine  is  strikingly 
deficient  in  chlorides.44  In  febrile  tuberculous  cases,  too. 
as  a  rule  there  may  be  noted  with  temperature  accession  a 
fall  in  the  elimination  of  sodium  chloride,  without  necessary 
manifestation  of  change  in  the  concentration  of  the  urine.45 
So,  too,  the  same  phenomenon  has  been  observed  in  the 
fever  induced  experimentally  by  hay  infusion  and  by 
trypanosomes.46  Efforts  have  been  made  to  explain  this 
symptom  in  a  variety  of  ways ;  for  example,  as  a  result  of 
salt  hunger  caused  by  under-nutrition,  as  a  result  of  reten- 
tion of  chlorine  in  degenerated  tissue  or  in  the  protein  in 
circulation  as  a  compensation  for  a  lowered  osmotic  pres- 
sure of  the  blood  due  to  a  markedly  increased  elimination 
of  phosphoric  acid,  etc.  Personally  the  author  is  of  the 
opinion  (in  agreement  with  v.  Hösslin)  that  all  such  ex- 
planations are  aside  from  the  mark,  and  that  we  are  really 

13  M.  Herz,  Wärme  und  Fieber,  Wien,  1893,  p.  91. 

44  Literature  on  Chlorine  Retention  in  Fever:  F.  Kraus,  1.  c,  pp.  662-663; 
P.  F.  Richter,  1.  c,  pp.  128-130. 

43  N.  Meyerowitsch,  Inaug.  Dissert.,  Zürich,  1911;  cited  in  Centralbl.  f.  d. 
ges.  Biol.,  1911,  No.  1918. 

4Uv.  Hosslin:    Zeitschr.  f.  Biol.,  53,  25,  1909. 

40 


626  FEVER 

dealing  with  a  disturbance  of  the  renal  function  caused  by 
altered  circulatory  relations.  The  author  has  come  to  this 
view  on  the  basis  of  observations  upon  reflex  influences  in- 
volving the  renal  capacity  which  he  studied  with  C.  Schwarz 
(Vol.  I  of  this  series,  p.  382,  Chemistry  of  the  Tissues).  In 
these  studies  the  observers  found  that  a  peritoneal  irrita- 
tion produced  experimentally  by  injection  of  pancreatic  tis- 
sue, oil  of  turpentine  or  aleuronat,  is  capable  of  influencing 
the  functional  ability  of  the  kidneys  in  such  a  manner  as  to 
lower  in  a  very  striking  degree  the  quantity  of  dissolved 
constituents,  particularly  the  sodium  chloride,  independently 
of  the  water  elimination.  From  this  the  author  would 
assume  that  a  disturbance  of  circulation  induced  by  the 
febrile  condition  may  act  in  very  much  the  same  way. 

As  may  be  seen  from  what  has  been  said  above,  the  hope 
of  more  closely  approaching  the  real  nature  of  fever  by 
examination  of  the  metabolic  processes  has  thus  far  not 
been  fulfilled,  and  we  are  forced  to  return  to  the  start- 
ing point  of  our  inquiries,  and,  in  connection  with  the  previ- 
ously described  line  of  thought  of  Traube,  seek  an  explana- 
tion of  the  process  in  a  disturbance  of  heat  regulation. 

It  is  impossible  to  consider  the  development  here  of  the 
whole  physiology  and  pathology  of  heat  mechanism,47  and 
the  author  feels  that  he  must  be  satisfied  to  present  only 
some  of  the  most  essential  items. 

Chemical  and  Physical  Heat  Regulation. — Following 
Rubner's  comprehensive  studies,  it  is  essential  to  differ- 
entiate between  chemical  and  physical  heat  regulation. 
While  for  maintenance  of  the  body  heat  in  case  of  low 
external  temperature  the  dominating  factor  is  apparently 

47  Literature  upon  the  Processes  of  Heat  Regulation:  O.  Löwy,  Ergebn.  d. 
Physiol.,  Ill,  339-354,  1904;  R.  Tigerstedt,  Nagel's  Handb.  d.  Physiol.,  1, 
593-606,  1905;  F.  Kraus.  Noorden's  Handb.  d.  Pathol,  d.  Stoffw.,  2  Ed.,  1, 
639-655,  1906;  L.  Krehl,  Pathol.  Physiologie,  5th  Ed.,  472-489,  502-566,  1907; 
O.  Cohnheim,  Physiol,  d.  Verdauung  und  Ernährung,  408-412,  1908;  Graham 
Lusk,  Ernährung  und  Stoffwechsel,  2nd  Ed.,  71-80,  1910;  P.  F.  Richter,  Handb. 
d.  Biochem.,  k" ,  137-140,  1910;  E.  Cavazzani,  Arch,  di  Fisol.,  8,  313,  523; 
cited  in  Jahresber.  f.  Tierchem.,  >t0,  520,  1910. 


TEMPERATURE  REGULATION  627 

first  a  rise  in  the  combustion  processes  going  on  in  the 
body ;  in  case  of  high  external  temperature  there  occurs  an 
increased  physical  heat  elimination,  in  connection  with 
which  besides  evaporation  through  the  skin  and  lungs  we 
have  also  to  consider  the  loss  of  heat  by  conduction  and 
radiation  and,  too,  by  transfer  of  heat  to  the  inspired  air 
and  to  the  ingested  food.48  According  to  Rubner's  experi- 
ments the  boundary  line  between  chemical  and  physical 
regulation  is  modified  by  the  state  of  nutrition,  in  the  sense 
that  in  a  poorly  nourished  individual  the  physical  elimina- 
tion of  heat  first  becomes  apparent  at  higher  temperature 
than  in  a  well  nourished  one,  which,  moreover,  corresponds 
with  the  experiences  of  daily  life.49 

Importance  of  the  Nervous  System  in  the  Regulation  of 
Temperature. — There  is  no  doubt  of  the  fact  that  the 
nervous  system  exerts  an  important  influence  upon  the  pro- 
cesses of  heat  regulation.  This  is  indicated  by  the  fact,  well 
known  since  Pflüger 's  time,  that  in  warm-blooded  animals 
with  the  cervical  cord  divided  the  temperature  regulation 
seems  as  good  as  lost,  and  these  animals  then  behave  toward 
changes  in  the  external  temperature  as  do  poikilothermous 
animals.  It  also  appears  that  such  animals  can  scarcely 
be  brought  into  a  febrile  condition  by  infectious  material. 
A  rather  extensive  failure  of  heat  regulation  may  be  noted 
even  from  the  influence  of  deep  narcosis.  The  excessive 
rises  in  temperature  observed  by  many  pathologists  and 
experimentally  studied  by  Naunyn  and  Quincke  in  injuries 
of  the  cervical  cord,  as  in  fractures  of  the  cervical  ver- 
tebrae, in  which  temperatures  of  42-44°  C.  sometimes  occur, 
are  of  much  interest;  they  are  referred  in  their  produc- 
tion to  the  combined  influences  of  a  more  highly  set  heat 
regulation,  decreased  heat  elimination  and  increased  heat 
production  in  the  muscles.50 

Temperature  rises  have  been  observed  from  injury  to 

48  Cf.  Graham  Lusk,  1.  c,  p.  76. 
«Cf.  0.  Cohnheim,  1.  c,  pp.  412-113. 
r*L.  Krehl,  1.  c,  pp.  476-477. 


628  FEVER 

a  number  of  foci  in  the  brain.  By  far  the  most  constant  of 
these  is  the  so-called  "heat  puncture."  While  penetration 
of  the  anterior  part  of  the  brain  does  not  produce  any  im- 
portant effect  upon  temperature,  after  injury  to  the  corpus 
striatum  intense  and  persistent  rises  in  temperature  are 
met  with.  As  electrical  irritation  of  this  part  of  the  brain 
is  also  capable  of  causing  the  same  feature,  we  cannot  be 
mistaken  in  assuming  that  the  change  in  heat  regulation 
ensuing  from  the  heat  puncture  is  to  be  regarded  as  an 
irritation  symptom.  It  is  a  matter  of  secondary  impor- 
tance with  us  whether  we  hold  that  there  exists  a  special 
"heat  centre"  or  whether  we  adopt  the  view  that  (as  for 
example,  Tiger stedt 51  believes)  the  nervous  centres  which 
preside  over  the  muscles  and  other  heat-producing  organs, 
as  well  as  those  which  innervate  the  cutaneous  vessels,  sweat 
glands  and  dominate  the  respiratory  movements,  function- 
ate in  a  manner  which  amounts  to  the  same  thing  as  heat 
regulation.  According  to  the  works  of  Stefani  and  his 
pupils  the  vagus  may  be  said  to  take  an  important  part  in 
heat  regulation. 

Fixation  of  Heat  Regulation  at  a  Higher  Level. — P.  F. 
Richter  has  attempted  to  frame  a  fundamental  difference 
between  the  hyperthermia  of  heat  puncture  and  of  infectious 
fever,  indicating  that  in  the  former  but  not  in  the  latter 
the  body  has  lost  its  ability  to  regulate  temperature.  This 
view  has  not,  however,  received  confirmation  from  other 
sources.  It  is  manifest  that  up  to  a  certain  degree  the  power 
of  regulation  of  temperature  is  maintained  in  every  form 
of  hyperthermia.  Liebermeister  has  held  the  view  that  the 
characteristic  feature  of  heat  regulation  in  fever  is  its 
"establishment  at  a  higher  level,"  regulation  being  actu- 
ally retained  but  set,  not  for  37°  C,  but  for  a  higher  tem- 
perature. This  suggestion  has  been  taken  up  by  many 
authors,  as  Filehne,  Stern,  Krehl  and  Gottlieb.  Friedrich 
Kraus,  too,  refers  fever  to  "  a  condition  of  irritation  of  the 

a  Tigerstedt,  1.  c,  p.  602. 


FIXATION  OF  HEAT  REGULATION  629 

central  regulatory  apparatus  in  which  the  latter  works 
somewhat  like  a  harp,  in  which  by  pedalling  a  modulation 
into  a  different  key  is  brought  about;  by  fixing  the  whole 
rhythm  the  tune  is  changed  from  one  key  to  another. " 52  Ac- 
cording to  Schwenkenbecher  in  febrile  subjects  as  in  healthy 
individuals  a  rise  in  heat  production  is  compensated  by  a 
rise  in  heat  elimination.53 

This  does  not  say,  however,  that  the  heat-regulatory 
apparatus  in  fever  functionates  as  efficiently  as  in  normal 
conditions.  The  experiences  of  physicians  indicate  rather 
that  the  temperature  of  febrile  subjects  is  more  variable 
than  that  of  healthy  individuals,  and  that  the  former,  for 
example,  are  more  easily  chilled  by  withdrawal  of  heat. 

It  may  be  said  in  a  general  way  that  the  body  tempera- 
ture of  the  febrile  subject,  in  spite  of  the  fact  that  heat 
regulation  is  by  no  means  excluded,  rises  because  the  heat 
elimination  lags  behind  the  heat  production.  ' '  The  process 
of  temperature  regulation,"  says  Krehl,54  " cannot  by  any 
means  be  thought  of  as  a  simple  one.  Under  all  circum- 
stances there  exist  influences  which  act  in  an  appreciably 
separate  manner  upon  heat  production  and  upon  heat  elim- 
ination. Each  of  the  two  processes  acts  under  different 
circumstances  through  different  physiological  agencies,  the 
elimination  of  heat  by  conduction,  radiation  and  evapora- 
tion of  water,  the  production  of  heat  by  the  decomposition 
of  nutrient  material  or  body  substance.  In  my  opinion  in 
fever  the  whole  group  of  these  mechanisms  is  changed,  and 
as  a  matter  of  fact  the  functional  disturbances  in  different 
cases  are  surely  not  the  same  in  their  individual  details. 
By  and  large  the  ability  to  regulate  is  retained.  Almost 
always,  or,  as  I  believe,  always,  there  prevails  a  state  of 
excitation  of  the  parts  by  which  the  heat  production  is 


B2Fr.  Kraus,  1.  c,  p.  644. 

53 Schwenkenbecher  and  Tuteur   (Med.  Clinic,  Strassburg),  Arch.  f.  exper. 
Pathol.,  57,  285,  1907. 
M  Krehl,  1.  c. 


630  FEVER 

increased,  that  therefore  there  exists  a  particular  com- 
bination of  disturbance  of  heat  production  and  of  heat 
elimination. ' ' 

Increased  Excitability  of  Heat  Regulating  Centres  in 
Fever  and  its  Reduction  by  Antipyretics. — As  causative  of 
such  disturbance  we  may,  in  accordance  with  R.  Gottlieb's 
statement,  think  of  a  condition  of  pathologically  increased 
excitability  involving  the  heat  regulating  centres.  It  is  fun- 
damentally one  and  the  same  thing  whether  this  excitation 
is  brought  about  by  electrical  or  mechanical  initiation  (as  in 
the  heat  puncture)  or  whether  it  is  the  result  of  stimulation 
by  toxic  bacterial  products.  It  is,  however,  of  the  utmost 
significance  that  the  antipyretics  (as  Filehne  also  has  held) 
owe  their  effect  clearly  in  the  first  place  to  a  quieting  of 
the  heat-regulating  centres  which  are  in  a  state  of  patho- 
logical irritation,  and  that  the  typical  fever  remedies  are 
also  on  the  whole  "analgesics"  and  "sedatives,"  that  is, 
weak  narcotics  for  the  sensory  area  of  the  cerebral  cortex. 
In  conformity  with  this  thought,  for  example,  even  small 
doses  of  morphine  are  capable  of  interfering  with  the  hy- 
perthermia of  cerebral  puncture.55 

Pyrogenic  Properties  of  Proteins  and  Protein  Deriva- 
tives.— We  may  at  this  point  turn  to  a  brief  consideration  of 
those  chemical  agencies  which  possess  the  ability  to  act  as 
excitants  of  fever  when  introduced  into  the  blood  stream. 

Krehl  and  Matthes  were  first  inclined  to  connect  the  ob- 
servation that  many  febrile  diseases  are  accompanied  by 
an  albumosuria  directly  with  the  production  of  fever  in 
infectious  diseases;  but  later  they  withdrew  this  opinion 
as  incorrect.  The  question  of  the  presence  of  albumoses  in 
the  blood,  as  previously  stated,  is  apparently  not  as  yet 
satisfactorily  understood ;  but  undoubtedly  an  albumosuria 


55  R.  Gottlieb  in  H.  H.  Meyers'  and  R.  Gottlieb's  Experimentelle  Pharma- 
kologie, pp.  389  et  seq.,  1910;  cf.  therein,  as  well  as  in  O.  Löwy,  Ergebn.  d. 
Physiol.,  8,  357-372,  1904,  and  in  Noorden's  Handb.  d.  Pathol,  d.  Stoffw.,  2, 
781-797,  1907,  for  a  detailed  analysis  of  the  action  of  antipyretics,  also  for 
appropriate  Literature. 


PYROGENIC  PROPERTIES  OF  PROTEINS  631 

can  exist  without  fever,  and  it  is  probable  that  it  were  bet- 
ter related  to  a  coincidence  of  the  appearance  of  products 
of  abnormal  protein  cleavage  in  the  blood  along  with  dis- 
turbance of  the  renal  function.50 

American  authors  hold  that  fever  may  be  a  result  of 
parenteral  digestion  of  protein,  without  the  protein  being 
of  necessity  of  bacterial  origin;  that  thus  we  are  able  by 
repeated  subcutaneous  injection  of  egg-albumin  in  rabbits 
to  induce  a  typhoid-like  fever.  The  difference  between  the 
action  of  the  white  of  egg  and  of  the  typhoid  bacilli  in  the 
body  would  seem  to  consist  only  in  the  fact  that  the  egg 
albumin  is  incapable  of  further  development.57  Contrary  to 
this  idea  Schittenhelm,  Weichhardt  and  Hartmann,5S  who  in- 
jected intravenously  into  animals  egg  albumin,  sheep  serum, 
peptone,  aminoacids  and  bacterial  protein,  come  to  a  dia- 
metrically opposed  conclusion,  that  animal  proteins  and 
their  cleavage  products  have  absolutely  no  effect  toward 
raising  temperature  when  introduced  in  quantities  which 
have  proved  in  case  of  the  bacterial  proteins  to  be  decidedly 
febrogenic.  E.  Nobel,  in  the  laboratory  of  Edwin  Faust, 
was  able  recently  to  isolate  from  colon  bacilli  killed  by  heat 
and  from  cultures  of  these  microorganisms  an  abiuret  therm- 
ogenic substance.59  The  often-quoted  statement  that  fibrin 
ferment  acts  to  produce  fever  has  been  disproved  by  studies 
emanating  from  the  medical  clinic  at  Heidelberg.  However, 
the  destruction  of  non-specific  or  of  autogenous  blood  cells 
in  the  circulation  does  produce  fever;  and,  too,  in  the  de- 
struction of  the  very  labile  blood  platelets  pyrogenic  sub- 
stances seem  to  be  set  free.60 


56  Cf.  F.  Kraus,  i.  c,  pp.  609-610. 

51  V.  C.  Vaughan  and  his  associates   (Univ.  of  Michigan),  Jour,  of  Amer. 
Med.  Assoc,  53,  629,  1909;  Zeitschr.  f.  Immunitätsforschung,  9,  458,  1911. 

88  A.  Schittenhelm,  W.  Weichhardt  and  F.  Hartmann  (Erlangen),  Zeitschr. 
f.  exper.  Pathol.,  10,  448,  1912. 

89  E.  Nobel  (Lah.  of  E.  Faust,  Wiirzburg),  Arch.  f.  exper.  Pathol.,  68,  371, 
1912. 

60  H.  Freund   (Med.  Clinic,  Heidelberg),  Deutsch.  Arch.  f.  klin.  Med.,  105, 
44,  1912;  106,  556,  1912. 


632  FEVER 

Fever  Following  the  Introduction  of  Corpuscular  Ele- 
ments Into  the  Circulation. — It  would  seem,  moreover,  that 
even  the  simple  presence  of  corpuscular  body-foreign  par- 
ticles is  sufficient  to  give  rise  to  febrile  temperatures.  Wolf- 
gang Heubner  obtained  a  uniform  and  definite  increase  of 
temperature  by  injection  of  very  fine  suspensions  of  paraf- 
fine,  and  he  suggests  in  the  same  line  that  in  the  paroxysms 
of  malaria  numerous  corpuscular  elements  gain  access  to 
the  blood  stream  at  one  time.61  The  foundry  fever  of  brass 
casters,  a  symptom-complex  suggestively  like  malaria,  is 
produced,  according  to  investigations  of  K.  B.  Lehmann, 
by  the  very  fine  particles  of  zinc  or  zinc  oxide  gaining  access 
to  the  lungs.62  It  may  well  be  that  these  particles  pass  from 
the  alveoli  of  the  lungs  into  the  blood. 

Hyperthermias  Produced  by  Chemically  Definite  Sub- 
stances.— We  are  aware,  moreover,  of  a  number  of  chem- 
ically definite  substances  which,  appropriately  applied,  are 
able  to  give  rise  to  fever.  Here  belong  substances  of  the 
purin  group.  Thus  Binz  found  that  caffeine  in  doses  in- 
sufficient to  produce  cramps  or  convulsions  can  act  thermo- 
genetically,  which  feature  he  attributed  to  a  heightened 
nervous  influence  upon  the  muscles.  So,  too,  A.  R.  Mandel 
succeeded  in  producing  temperature  rises  in  monkeys  by 
means  of  xanthin,  caffeine  or  decoctions  of  coffee,  from 
which  he  regarded  himself  justified  in  ascribing  an  impor- 
tant role  to  the  purin  bases  set  free  in  toxic  tissue  destruc- 
tion in  relation  to  the  production  of  fever  (often  accom- 
panied by  an  increased  elimination  of  purin  bodies).63 
Atropine  and  cocaine  can  also  at  times  cause  an  access  of 
temperature64  and,  too,  a  number  of  the  derivatives  of 
anthrachinone.65    The  most  striking  effect  is,  however,  seen 

81 W.  Heubner  (Göttingen),  Münchener  med.  Wochenschr.,  1911,  No.  46. 

WK.  B.  Lehmann  (Würzburg),  Verhandl.  d.  Ges.  d.  Naturforsch.,  78,  362, 
1906. 

63 A.  R.  Mandel  (New  York),  Amer.  Jour,  of  Physiol.,  10.  452,  1904,  20, 
439,  1909. 

MCf.  0.  Löwy,  Ergebn.  d.  Physiol.,  S',  355,  1904. 

**J.  v.  Magyari-Kossa  (Budapesth),  Arch,  intern,  de  Pharmacodyn.,  20, 
157,  1910. 


SIGNIFICANCE  OF  FEVER  633 

in  case  of  tetrahydronaphthylamine  (first  noted  by  Stern), 
which  (according  to  researches  emanating  from  the  labora- 
tory of  H.  H.  Meyer)  acts  both  as  an  excitant  to  the  heat 
regulating  centre  and  induces  a  condition  of  constriction  of 
the  blood-vessels  of  the  skin,  muscles,  and  kidneys.66  An 
increase  of  muscular  action  seems  also  concerned  in  the  rise 
of  temperature.67  Adrenin  can  also  at  times  bring  on  a  rise 
of  temperature. 

Salt-  and  Sugar-fever. — Finally  may  be  mentioned  the 
very  remarkable  "salt-  and  sugar-fever,"  which  has  re- 
cently received  much  consideration  but  which  is  as  yet  with- 
out explanation,  a  temperature  exaggeration  which  has  been 
noted  in  animals  and  human  beings  (especially  in  infants, 
but  also  in  adults)  after  intravenous,  subcutaneous,  oral  and 
rectal  introduction  of  solutions  of  sodium  chloride  or  of 
sugar,  and  which  is  apparently  accompanied  by  an  increased 
production  of  heat  and  increased  protein  metabolism.68 

Significance  of  Fever. — In  conclusion  we  may  take  up 
the  question  as  to  what  particular  importance  fever  pos- 
sesses for  the  economy. 

Since  time  immemorial  physicians  as  well  as  patients 
have  been  thoroughly  impressed  with  the  idea  that  fever  is 
harmful,  and  measures  for  its  suppression  have  always 
occupied  a  large  place  in  therapy.  The  development  of 
scientific  pathology  at  first  seemed  to  support  ideas  of  this 
kind,  and  we  were  disposed  to  look  especially  upon  the 
parenchymatous  and  fatty  degeneration  of  organs,  a  de- 
pression of  the  vasomotors  and  a  weakening  of  the  heart, 
as  well  as  a  loss  of  the  haemoglobin  of  the  blood,  as  the  im- 
mediate harmful  effects  of  the  heightened  temperature  it- 
self. More  recent  studies,  as  those  of  Naunyn  in  particu- 
lar, as  well  as  those  of  Roily  and  Meltzer,  have  disproved 

ce  Jonescu  (Pharmacol.  Instit.,  Vienna),  Arch.  f.  exper.  Pathol.,  60,  345, 
1909. 

"  H.  Mutch  and  M.  Pemhrey,  Jour,  of  Physiol.,  43,  109,  1912. 

68  Studies  by  Bingel,  Cobliner,  Finkelstein,  H.  Freund,  E.  Gräfe,  Friberger, 
Heim  and  John,  Hort  and  Penfold,  Nothmann,  Schloss,  Verzär. 


634  FEVER 

this  view,  and  have  proved  that  these  pathological  features 
are  not  to  be  ascribed  primarily  to  the  influence  of  the  fever 
heat  but  rather  to  intoxication  by  products  of  pathogenic 
microorganisms.  Although  even  at  present  it  is  impossible 
to  give  any  clear  and  precise  answer  to  the  question  whether 
fever  in  itself  is  useful  or  harmful,  the  belief  is  making  more 
and  more  headway  that  fundamentally  we  may  regard  the  fe- 
brile temperature  accession  as  a  curative  effort  on  the  part 
of  nature.  We  have  access  to  a  series  of  observations  which 
indicate  a  favorable  influence  of  hyperthermia  upon  infec- 
tious processes.  Here  may  be  mentioned  the  observations 
of  Löwy  and  Richter  upon  pneumonia,  diphtheria,  chicken 
cholera  and  swine  erysipelas,  those  of  Rovighi  upon  sep- 
ticaemia, of  Filehne  upon  erysipelas,  of  Roily  and  Meltzer 
upon  infections  with  anthrax,  streptococci,  pneumococci  and 
bacterium  coli.  From  this  standpoint  the  elevated  temper- 
ature can  either  act  directly  to  harmfully  influence  the  bac- 
teria, or  it  may,  on  the  other  hand,  increase  the  bactericidal 
power  of  the  blood,  or  the  production  of  antibodies.  Ob- 
servations like  those  of  Roily  and  Meltzer,  Lüdke,  Fuku- 
hara,  Lissauer  and  others  upon  the  formation  of  agglutin- 
ines  and  haemolysines  in  fever,  make  it  clearly  probable 
that  we  owe  to  the  elevated  temperature  an  important  part 
in  the  production  of  antibodies.69  Modern  pharmacologists 
also  are  taking  the  position,  as  H.  H.  Meyer  and  Gottlieb,70 
that  in  application  antipyretics  serve  far  better  if  em- 
ployed as  fever  narcotics,  and  that  it  is  better  to  counteract 
certain  associated  features  of  the  fever  (as  rapid  cardiac 
action  and  respiration,  restlessness,  headaches,  loss  of 
appetite,  etc.)  than  to  depress  the  high  temperature. 

Here,  too,  then  experimental  investigation  is  relentlessly 
clearing  away  errors  venerable  from  their  age  in  order  to 
make  new  paths  for  new  endeavors. 

m  Literature  upon  the  Significance  of  Fever  for  the  Economy:  P.  F.  Richter, 
1.  c,  pp.  140-146. 

70  H.  H.  Meyer  and  R.  Gottlieb,  Experimentelle  Pharmakologie,  p.  398,  1910. 


EPILOGUE  635 

Epilogue. — We  are  come  to  the  close  of  our  long  and 
arduous  journeying.  The  author  begs  to  be  permitted  be- 
fore separation  to  cordially  thank  every  one  who  has  accom- 
panied him  in  sympathetic  thought  thus  far.  He  has  con- 
ducted this  excursion  as  well  as  he  knew  how,  through  wide 
tracts  in  the  world  of  organic  activity ;  and  has  interpreted 
the  everchanging  abundance  of  visions  which  were  open  to 
his  eyes  to  the  best  of  his  understanding.  He  knows  full 
well  that  the  future  will  again  and  again  declare  his  inter- 
pretations wrong,  and  that  to  other  eyes,  provided  with 
better  spectacles,  many  things  will  necessarily  appear  in 
different  light.  And  too  he  is  well  persuaded  that  many  a 
subject  which  to-day  we  imagine  an  absolute  fact,  will  only 
provoke  an  indulgent  smile  from  our  successors.  "Man  is 
doomed  to  blunder  as  long  as  he  strives."  And  the  author 
must  therefore  be  satisfied  with  the  consciousness  of  the 
honesty  of  his  effort. 

That  which  may  in  some  measure  console  us  for  the 
inadequacy  of  our  knowledge  is  the  consciousness  that  all 
of  us  who  are  endeavoring  to  solve  the  enigmas  of  the  world 
of  life  are  engaged  in  a  glorious  service,  and  that  to  us  who 
live  to-day  has  been  granted  the  merciful  favor  of  enjoying 
together  a  great  cultured  epoch  in  which  the  world — in  spite 
of  every  social  and  political  calamity  which  so  often  takes 
our  breath — is  hastening  forward  in  winged  course  to  new 
ambitions. 

Let  us  then  for  ourselves  take  heed  that  all  the  build- 
ing stones,  whether  great  or  small,  on  which  the  living  gen- 
eration of  nature  searchers  of  to-day  tests  out  its  powers, 
may  come  to  contribute  to  the  establishment  of  the  marvel- 
lous structure  of  future  culture  and  learning  from  which 
we  hope  for  oncoming  generations  all  that  we  dream  of  but 
may  not  see :.  the  freedom  of  the  people  from  avoidable  evil 
of  body  and  soul,  from  want  and  from  error,  and  the  triumph 
of  true  humanity. 


INDEX 


Abderhalden  on  food  value  of  advanced 
products    of    protein    cleavage, 
64 
on  parenteral  introduction  of  pro- 
teins and  sugars,  511 
on  protective  ferments  in  blood, 

218 
on    proteolytic    tissue    ferments, 

91,  218 
test  in  pregnancy,  96 
Abscess,    alimentary   galactosuria   in, 
287 
proteolytic   factors   in,   87 
Absorption  of  albumoses,  57 
aminoacids,    57 
coefficient,  5S7 
of  fat,  parenteral,  379 
fever,  86 
from  intestine  influenced  by  age 

and  disease.  54 
of   protein   cleavage  products   in 

intestine,  53 
of   protein   cleavage   products   in 

stomach,  17 
of  protein,  iodized,  57 
Acapnia  in  alpinism,  604 
Accessory  respiration,  563  " 
Acetalanin,  476 

Aeetaldehvde,  condensation  into  aldol. 
435 
in   fat  formation   from  carbohy- 
drate, 390 
in   glucose   fermentative   catabol- 
ism,  347 
Acetamide.   112 
Aceto-acetic  acid.  431 

and    acetone,    separation   of, 

449 
from  aldol.  435 
catalvtic   enzvrne   action   on, 

447 
determination  of,  448 
in  diabetic  coma,  441 
from  ethyl  alcohol,  435 
and    /S-oxybutyric    acid,    re- 
versibility of,   442 
Acetonemia  and  lipaemia,  reversibility 

of,  374 
Acetone,    431 

and  aceto-acetic  acid,  separation 

of,  449 
bodies,  431 

benzol  derivatives  in  forma- 
tion of,  439 
and  butyric  acid  and  capric 
acid   ingestion,   434 


Acetone  bodies  and  cancer,  432 

chemical     relation     between, 

431,   442 
from       compounds        with 
branched  and  cyclic  chains, 
437 
crotonic    acid    in    formation 

of,  438 
and  diabetic  coma,  431,  440 
dimethylacrylic  acid   in  for- 
mation of,  438 
ethylbutvric  in  formation  of, 

438 
from  fatty   acids  with  even 

carbon  chains,  432 
from  glycerol,  439 
interrelation  of,  445 
isoamylamine    in    formation 

of,   438 
isovaler  aldehyde     in     forma- 
tion of,  438 
isovalerianic   acid  in  forma- 
tion  of,   438 
from  leucin,  438 
and  lipamiia,  432 
0-oxyisovalerianic  acid  in  for- 
mation of,  438 
phenvlalanin  in  formation  of, 

439 
and    phosphorus    poisoning, 

432 
from  protein   cleavage  prod- 
ucts, 437 
relation  to  fat  of  body  and  of 

food,  431 
and   starvation,   432 
tyrosin  in  formation  of,  439 
determination   of,   448 
from   fat   catabolism.   393 
iodoform    method    of    determina- 
tion, 448 
mercuric   cyanide  method   of   de- 
termination,  448 
Messinger-Huppert  method  of  de- 
termination, 448 
nitrophenyl-hydrazine  method  of 

determination,  448 
production     from     a-aminoacids, 

434 
production   from   oxybutyric   and 

aceto-acetic  acids,  447 
sodium  bisulphite  method  of  de- 
termination, 448 
Acetophenone,  112 
Acetyl-aminobenzoic  acid,  111 

reduction      product      of 
nitrobenzaldehyde,  471 

637 


638 


INDEX 


Acetyl  figure  of  fats,  385 
Acetylenehaemoglobin,   592 
Acetylization   processes  in   anabolism 
and      catabolism      o  f 
aminoacids,  474 
animal  body,  474 
Acetylphenylaminoacetic  acid,  475 
Acholia,  120 
Achroödextrine,  196,  219 

like  substance  in  urine,  512 
Acid,  see  specific  name  of  acid 
Acid  albumin  of  gastric  contents,  16 
albuminates  of  gastric  contents, 

14 
production  of  snails,  12 
Acidity  of  gastric  juice,  origin  of,  9 
determination  of,   11 
physico-chemical    expla- 
nation of,   11 
Acidosis,    102,    103 

and  ammonia  elimination,  442 
and  carbohydrate  deficiency,  439 
in  diabetes,  259 
in  fasting,  505 

and  fat  destruction  in  fever,  620 
and  loss  of  hepatic  function,  102 
urea  elimination  in,  442 
Acridin,  oxidation  of,  into  oxyacridon, 

469 
Acromegaly  and  glycosuria,  314 

hypophysis  in,  314 
Addison's    disease,    hypoglycemia   in, 

306 
Adenase,  149 
Adenin,  149 

conversion  into  uric  acid,  149 
Adipocere,    414 

Adrenal,  chromium  affinity  of,  306 
diabetes,  300 

pancreas  in,  310 
suppression    of,    by    nephro- 
toxics,  303 
glycosuria,  hypophysis  in,  315 
kidney   in,   302 
suppressed  by  ergotoxin,  263 
regulative  influence  over  carbohy- 
drate metabolism,  304,  309 
Adrenalin,  see  Adrenin. 
Adrenals,     exclusion     of,      inhibiting 
puncture  glycosuria,  305 
regulative  effects  of  carbohydrate 

metabolism,    309 
squeezing  of,   followed  by   glyco- 
suria, 304 
and  sugar  puncture,  304 
thyroid    and    pancreas,     interac- 
tion of,  313 
Adrenin,  214,  215,  300,  555 

mode  of  action  in  producing  gly- 
cosuria, 301 
increase    in    blood,    after    sugar 
puncture,  307 
Adsorbing  media,  44 


Adsorption     of     acids     in     capillary 
media,  13 
capacity  of  enterokinase,  42 
phenomena,  11,  271,  592 
theory,  592 
Agar-agar  in  diabetic  diet,  271 
Agglutinin  formation  in  fever,  634 
Alanin,  45,  59,  60,  64,  93,  239,  456, 
458,  460,  473,  474 
catabolism   of,   466 
production  from  non-nitrogenous 

material,  474 
sugar  formation  from,  240 
Alanyl,    93 
Alanyl-glycin,   45,   93 
Alanyl-glycylglycin,    93 
Alanyl-leucin,  93 
Albumin,  Benee-Jones,  55 

removal  of,  from  urine,  206 
Albumoses,  absorption  of,  57 

in  blood,  absorption  of,  from  in- 
testine, 56 
in  gastric  digestion,  16 
stimulative    in    pancreatic   secre- 
tory activity,  41 
in  urine  in  autolytic  processes  in 

body,  86 
in  urine  of  fever,  620 
Alcaptonuria,    470 
Alcohol  in  animal  tissues,  329 

antiketogenic   influence  of,  436 
in  diabetes,  268 
in  fattening,  400 
as   a   food,   400 
in  glucose  metabolism,  345 
glycogen  formation  and,  231 
Alcoholic  fermentation  in  animal  tis- 
sues, 328 
of  sugar,  345 
by   zymase,   327 
Alcoholism  and  gout,   186 

lipsmia   of,   377 
Aldehydases,    551 

Aldol,    condensation    of    acetaldehyde 
into,  435 
in    fat   formation    from   carbohy- 
drate, 390 
in   glucose   fermentative   catabol- 
ism, 348 
as   source   of   /3-oxybutyric   acid, 

391,  435 
transformation    into    aceto-acetic 
acid,  435 
Aleuronat  in  diabetic  diet,  271 
Aliphatic  fatty  acids,  Knoop's  theory 
of  catabolism  of,  392 
side  chains  and   fatty  acids,  de- 
composition of,  464 
Alkalescence,  changes  of,  in  gout,  178 
Alkali    of    bile    in    emulsification    of 
fats,  367 
inhibiting  gastric  secretion,  8 
in  sugar  catabolism,  341 


INDEX 


639 


Alkalinity   of   tissues   in    relation   to 

gouty  deposits,  184 
Alkalosis,   102 

Alkylation   in   animal  body,   476 
Allantoin,   81,    153 

from  autolysis,  160 
as   end-product   of   purin   metab- 
olism in  mammals,  158 
fate  of  experimentally  introduced, 

163 
formation    of,    in    mammals,    158 
location  of  formation  of,   160 
production   by   protoplasmic  poi- 
sons of,  159 
uricase  in  production  of,  161 
from  uricolysis,   158 
Wiechowski's   method  of   estima- 
tion, 169 
Alloxyproteic  acid,   137 
Alpinism,  acapnia  in,   604 

alkalinity   of   blood    in,   606 
atmospheric   pressure  in   produc- 
tion of,  605 
blood  corpuscles  in,  601 
capacity  for  work  in,  607 
cardiac  activity  in,  602 
climatic   factors   in,    601 
minimal  metabolism  in,  607 
nitrogen  retention  in,  608 
observation  material  in,  599 
physiology  of,  579,  599 
respiration   in,   604 
sleeplessness    in,    604 
Amides  in  metabolism  of  vegetarians, 
67 
plants,  67 
Amido-fat  combination,  412 
Aminoacids,  absorption  of,  57 
acetone  production  from,  434 
acetylization  processes  in  anabol- 

ism  and  catabolism,   474 
benzoylated,  111 
in  blood,   559 
catabolism  of,  462,  466 
catabolism  of,  by  yeasts,  467 
deaminization  of,  82 
determination,    quantitative,    of, 

119,    120 
elaboration  of,  by  lower  vegetable 

forms,  471 
elimination  of,   115 

in  disease,  116 
as  test  of  hepatic  func- 
tion, 116 
in   gastric   digestion,    16 
in  intestinal  contents,  53 
in  intestinal  contents,  determina- 
tion of,  53 
ketonic  acids  in  production  of,  69 
optically    active,    inhibiting   pro- 
teolysis, 94 
in  plants,  67 
sugar  formation  from,  238,  239 


Aminoacids,  synthesis  of,  69 
in  body,  472 
in    urine,    115 

in    urine,    increased    in    diabetes, 
269 
m-Aminobenzoic  acid,  98 
Aminobenzoic  acid,  111 
Aminobutyric   acid,    473 
Aminocaproic  acid,   473 
Aminophenol,    reduction    product    of 

nitrobenzol,    471 
Aminuria,    alimentary,   in   functional 

test  of  liver,  116 
Ammonia  in  correction  of  acidity  of 
body,    104 
elimination  and  acidosis,  102.  441, 
442 
in    diabetic   coma,   441 
in  fever,  102 
in  hepatic  disease,  102 
from  other  causes  than  acid- 
osis, 442 
in    protein    metabolism,    498 
exhaled,   520 
Ammonium  acetate  in  feeding,  69 
Ammonium  carbonate,  100 

in  formation  of  urea,  97 
carbonate  in   formation  of  urea, 

97,   100 
citrate  in  feeding,  68 
salts,  nutritive  value  of,  68 

in  synthesis  of  proteins,  67 
Amphibia,  gastric  digestion  in,   19 
Amygdalic  acid,  475 
Amylopsin  in  carbohydrate  digestion, 

195 
Anaerobic  respiration,  329 
Anaphylactic  phenomena  from  protein 

absorbed  from  intestine,  55 
Anaphylaxis,  95,  510 

from      proteins     absorbed      from 
bowel,  55 
Aniline,     hydroxylation     into     para- 

amidophenol,  468 
Anoxybiosis,  329,  577 
Anthrachinone    as    a    heat-producing 

agent,  632 
Anticatalase,  560 
Antifat  treatment,   397 
Antiferments,  24 

Antiketogenic  property  of  alcohol,  436 
property  of  carbohydrates,  439 
substances,    442 
Antileucoproteases,  88 
Antipancreatin,  260 
Antipepsin,  24,  25 
Antipneumin,    563 

Antipyretics  acting  to  reduce  excita- 
tion  of  heat  regulating  centres  in 
fever,  620 
Antisepsis  required  in  autolysis,  76 
Antitrypsin,  49,  88 


C40 


INDEX 


Antitryptic     treatment    of     suppura- 
tions,  etc.,    88 
Aqueous  humor,  sugar  in,  211 
Arabinose  and  galactose,  291 

in  glucose  cleavage,  electrolytic, 
344 
chronic  pentosuria,  290 
Arabonic  acid  in  electrolytic  cleavage 

of  glucose,  344 
Arginase,  76,  105 
Arginin,  84,  105,  119,  131 

as  source  of  creatin,  131 
Arnold  reaction,   135 
Aromatic  substances  in  urine,  319 
Aseptic  autolysis,  77 
Asparagin,   autolytic   cleavage  of,   82 

nutritive  value  of,  68 
Asparaginic     acid,     sugar     formation 

from,  240 
Asphyxia  and  autolysis,  89 
blood  in,  508 

Winterstein's  theory  of,  576 
Assimilation  limit  of  sugars,  232 
Atmospheric  pressure  in  alpinism,  605 
Atwater    and    Benedict's    respiration 

calorimeter,  516 
Autodigestion,  75 

of  stomach,  antipepsin  in,  25 

resistance   against,  24 
Autolysates,    antibacterial    and    anti- 
toxic influences  of,  86 
Autolysis,   75 

allantoin  production  by,  160 
asepsis  and  antisepsis  needed  in, 

76,  77 
and  asphyxia,  89 
bacterial  processes  in  relation  to, 

86 
Benson  and  Well's  method  of  fol- 
lowing, 79 
carbonic  acid  influencing,  89 
colloids  influencing,  89 
drugs  influencing,  90 
extrinsic  factors,  89 
of  exudates,  85 
fat  phanerosis  in,  409 
in  involution  of  uterus,  85 
in  pathological  processes,  83 
products  of,  76 

in  blood  and  urine,  86 
progress  of,  methods  of  observing, 

79 
protection    of    living   cells    from, 

81 
in    regressive    changes    in    living 

body,  85 
stimulated  by  phosphorus,  chloro- 
form, narcotic  agents,  etc.,  84 
variability  of,  79 
a  vital  process?  78 
as  a  vital  process,  objections  to, 
80 


Autolytic  tissue  ferments  and  physio- 
logical activity  of  tissue,  79 

Autolytic  tissue  ferments  and  erepsin, 
51 

Autoxidizable  body  substances,  535 

Autoxyproteic  acid,   137 

B 

Bacteria  and  autolysis,  86 

Creatinin    production,    129 
fat  catabolism,  392 
in  fat  formation  in  autolysis,  410 
,    in  lab-process,  30 
nutritive  value  of,  68 
Bang's   method   of   sugar    estimation, 

206 
Barcroft     and     Haldane     method     of 

blood-gas   analysis,    572 

Barium,    double  salt   of   cresol-glycu- 

ronic  and  cresol-sulphuric  acids,  319 

Basedow's  disease  and  glycosuria,  312 

Batrachian     larvae,     fasting     studies 

upon,  507 
Bence-Jones   albumin,  55 
Benedict    and    Gephart's    method    of 

urea  estimation,   107 
Benedict  and  Meyer's  method  of  trans- 
forming creatin  into  Creatinin,  123 
Benedict's    transportable    respiration 

apparatus,  518 
Benson    and    Well's    method    of    fol- 
lowing autolytic  processes,  79 
Benzaldehyde,  action  in  indigo,  535 
Benzidin-monosulphite   of   soda    reac- 
tion on  gonorrhoeal  pus  and 
other   cells,   542 
Benzoic  acid  107 

dehydration   derivative  from 

hexahydrobenzoic  acid,  469 

dehydration   derivative  from 

quinic  acid,  469 
and    glycocoll    in    formation 

of  hippuric  acid,    107 
source    of,    in    formation    of 
hippuric    acid,    107 
Benzol  derivatives  and  acetone  bodies, 
439 
disruption  into  muconic  acid,  469 
hydroxylation  into  phenol,  468 
Benzoylated  aminoacids,    111 
Benzoyl-leucin,    111 
Bertrand's   method   of   sugar   estima- 
tion, 206 
Bile  in  fat  digestion,  359 

emulsification,    367 
solution,  367 
reflux  of,   into   stomach,   35 
in    solution    of    fatty    acids    and 

lipoids,  367 
in  starch  digestion,   197 
salts,   activation  of  steapsin  by, 
363 
Biogen,  569 


INDEX 


641 


Birds,  gastric  digestion  in,  19 
Blood,  alkalinity  in  alpinism,  loss  in, 
606 

aminoacids  in,  59 

carbohydrates  other  than  glucose 
in,  20S 

carbonic  acid  combination  in,  592 

cells  in  hsemic  glycolysis,  340 
increase  at  elevations,  601 
and  serum,  carbonic  acid  ex- 
change between,   594 

changes,  plasmatic,  in  fever,  622 

chemico-legal    detection    by    per- 
oxidase reactions,  545 

coefficients  of  oxygen  absorption, 
invasion  and  evasion,  587 

detection  by  v.  Fiirth's  method, 
546 

detection    by    pyridin-leukomala- 
chite  green  method,  546 

dust  particles,  369 

ester-splitting  ferment  of,  370,402 

in  fasting,  501 

fat  cleavage  in,  401 

fat  masking  in,  370 

fat,  passage  of,  from,  375 

gases,  579 

gas  analysis,  Barcroft  and  Hal- 
dane,  572 

technic  of,  584 
exchange   between   cells   and 
serum,  394 

glucosamine  in,  209 

glucose    in,    205 

glycogen  in,  209 

glycolysis  in,  338 

ferment  in  fibrin  in,  340 
leucocytes  in,   339 

lipase  in,  401 

lipolytic  function  of,   370 

maltases,  invertases  and  gluceses 
in  serum  of,  218 

maltose  in,  209 

methylene-blue    reaction    in    dia- 
betes, 266 

oxygen   capacity   of,    influence  of 
carbonic  acid  on,  589 

oxygen  capacity  of,   influence  of 
salts  on,  590 

oxygen  capacity  of,   influence  of 
temperature  on,  589 

oxygen  capacity  of,  maximum,  588 

oxygen     capacity     of,     physical- 
chemical   conception   of,    590 

oxygen  consumption,  561 

oxygen  tension  curves  of,  588 

Plesch's    method   of   hsemoglobin- 
ometry,  586 

proteins  of,  56 

proteins    and    protein-derivatives 
passing  into,  54 

rest  nitrogen  in,  58 

serum,  peptolytic  power  of,  95 


Blood,  sucre  immediat  and  sucre  vir- 
tuel  in,  208 
sugar  of,  205 
sugar    estimation,    205 
sugar,  free  of,  207 
Body-foreign  substances,  fate  in  body, 

463 
Body  protein,  surface  development  and 

volume  of,  521 
Bohr   on    oxygen    fixation   by   haemo- 
globin, 591 
Brass-workers'  fever,  632 
Braunstein's  method  of  urea  estima- 
tion, 107 
Bread  substitutes  in  diabetic  diet,  271 
Bromine-crotonic  acid  method  of  quan- 
titative determination  of  oxybutyric 
acid,  450 
Bunge  and   Sclimiedeberg  method   of 

estimation  of  hippuric  acid,  113 
Butyric  acid,  393,  426 

in  glucose  fermentation,  347 
poisoning  and  coma,  433 


Cadaveric  wax,  414 
Cadaver  in,   118 
Caffeine,  167 
Calcium  paracaseinate,  28 

salts  as  activators  of  tripsinogen, 
42 
Calculi,   uric  acid,    182 
Calorimeters,  514 
Cammidge  reaction,  293 
Camphor-glycuronic  acid  in  urine  as 
possible  functional  test  of  liver,  323 
Cancer  and  acetone  bodies,  432 
colloid  metals  destroying,  90 
high     molecular     residual     sub- 
stances in  urine,  146 
urochromogen  in,   145 
Cane-sugar,  assimilation   of,  229 

behavior     after     parenteral 

introduction,  229 
fate   after   parenteral   intro- 
duction,  197 
Capanna  Margherita,  599 
Capric  acid,   426 
Caproic  acid,  426 
Caprylic  acid,  426 
Carbamino-reaction,  Siegfried's,  594 
Carbohydrases,  211 
Carbohvdrate,  antiketogenic  influences 
of,  439 
cleavage  of,  in  intestine,  195 
cleavage  of,   in  mouth,   194 
cleavage  of,  in  stomach,  195 
conversion  into  fat,  387 
deficiency  and  acidosis,  439 
digestion  of,  194 
digestion,  amylopsin  in,   195 
in  intestine,  195 
pancreas  in,  195 


642 


INDEX 


Carbohydrate  digestion,  ptyalin  in,  194 
in  stomach,  195 
fat  formation  from,  386 
and   fatty   acids,   route   between, 

447 
food  limiting  protein  destruction 

in  fever,  618 
of  food,  milk-fat  originating  from, 

425 
formation  de  novo,  236 
metabolism  in  fasting,  504 
fever,  621 
and  hypophysis,  314 

internal        secretory 
glands.  300 
regulation    of,    by    adrenals, 

304,  309 
thyroid  in  relation  to,  311 
other  than  glucose  in  blood,  208 
products,     resorption     from     in- 
testine, 197 
in  protein  molecule,  233 

determination  of,  233 
resorption   and    removal   of   pan- 
creas,   196 
-splitting  ferments,  211 
of  liver,  214 
of  muscle,  215 
of  pancreas,  196,  364 
in   plants,  transformation  of  fat 
into,  387 
Carbon  elimination  in  protein  metab- 
olism,  498 
Carbon  monoxide  haemoglobin,  592 
Carbonic  acid,  autolysis  influenced  by, 
89 
combination  in  blood,  592 
exchange  between  blood  cells 

and  serum,  594 
pressure    influencing    oxygen 
capacity  of  blood,  589 
Carbonyldiurea,  lli5 
Cardiac  activity   in  alpinism,  602 
Carnitin,  133 
Casein,  28,  233,  494,  495 

in  milk,  form  of,  429 
Catabolism    of    higher     fatty    acids, 

liver  in,  385 
Catalase,    538,    556 

and  colloid  metals,  558 

combustion  processes,  559 
peroxidases,  559 
physiological   significance  of,  559 
preparations,  557 

determination  of  activity  of, 
557 
reaction,  kinetics  of,  558 
of  tissue,  increase  after  birth,  560 
Catalytic    agents     in     catabolism     of 
sugar,  342 
enzymes    in    catabolism    of    oxy- 
butyric  and  aceto-acetic  acids, 
447 


Catalytic    pancreatic    constituent    in 

sugar  catabolism,  343 
Cell  fat,  412 

and  depot  fat,  384 
organization,    the    basis    of    life, 
571 
Cells,  peroxidases  in,  539 

various,  in  production  of  creatin- 
creatinin,   129 
Cellular  proteolytic  enzymes,  51 

protoplasm  in  fever,  changes  in, 
624 
Cellulose,  cleavage  by  lower  forms  of 
life,  201 
determination  of,  200 
digestion  of,   198 
by  cytase,  200 
by  enzymes  of  food,  202 
importance   of    infusoria   to, 

204 
by      intestinal      microorgan- 
isms, 202 
food   value   of,   203 
marsh-gas  production  in  digestion 

of,  202 
as   substitute   for  other  carbohy- 
drate food  in  diabetes,  200 
Cheese,  formation  of,  28 

ripening    of,    and    fat    formation 
from  protein,  415 
Chemico-legal    detection    of    blood    by 

peroxidase  reactions,  545 
Child,   protein   requirement  of,   486 
Childbed,  lactosuria  of,  2S4 
Chitin,  233 
Chittenden's  experiments  in  nutrition 

and   energy,   4S4 
Chloral,  318 
Chloral,     reduction     to     trichlorethyl 

alcohol,   471 
Chlorine  retention  in  fever,  624 
Chlorocruorin,   547 
Chloroform  increasing  autolysis,  84 
Cholesterinasmia  in  diabetes,  374 
Cholesterol-ester  steatosis,  421 
Cholesterol   steatosis,  422 
Cholic  acid,  113,  119 
Choi  in,    86 

Cholin  and  secretin,  differentiation  be- 
tween, 39 
secretin    and    vasodilatins,    rela- 
tions of,  39 
Chondroitin-sulphuric   acid   in   urine, 

147 
Chorda   tympani    and   sugar   of   sub- 
maxillary  salivary  gland,   stimula- 
tion of.  278 
Chromaffin   system,   relation   to  other 
glands  with  internal  secretion,  316 
Chromium  affinity  of  adrenal,  306 
Chyluria,  375 

Chyme,  passage  into   intestine  of,  33 
(  hymosin,  26 


INDEX 


643 


Citric   acid    fermentation,    348 

synthesis  of  glycolic  acid.  348 
Classification  of  proteolytic  ferments, 

94 
Climate  and  food,  487 
Coccygeal  gland,  fat  of,  427 
Coefficients  of  oxygen  absorption,  in- 
vasion and  evasion,  587 
Cohnheinrs  respirometer  for  isolated 

organs,   572 
Cold,  glycogen  and  exposure  to,  225 

glycosuria  from,  299 
Colloidal  metals  and  catalases,  558 
Colloids,  autolysis  influenced  by,  89 

urinary,  147 
Colorimetric  method  of  diastase  esti- 
mation, 212 
of   sugar   estimation,   200 
Coma  diabeticum  and  acetone  bodies, 
431 
alkaline  treatment  of,  441 
and  lipsemia,  373 
Combined  acid  of  gastric  juice,   14 
Combustion  processes, see  also  respira- 
tion   of    tissues,    gas    ex- 
change,   etc. 
in  alpinism,  007 
and  catalases,  559 
in   fever,   010 
and  oxidases,  555 
Condensation  of  aldol  into  fat,  390 

of   digestion   products,    01 
Conjugate     benzoic-acid     derivatives. 
478 
sulphates,   477 
Conjugation   of  glycuronic  acid,  con- 
ditions of.  318 
Corpulence,  see  Obesity 
Corpuscular    substances,    pyrogenesis 
from  introduction  into  blood  of,  031 
Creatase,    124 
Creatin,  122 

from  arginiu,  131 

and  Creatinin,  relations  of.  123 

determination,    quantitative,    of, 

123 
from  guanidin-acetic  acid,  131 
metabolism  and  female  generative 
organs,  130 
in    functional    hepatic    test, 
129 
from  muscle,  128 
Creatinase,  124 
Creatinin,   122 

determination,    quantitative,    of, 

122 
production  by  bacteria,  129 
Creatin-creatinin,      endogenous      and 
exogenous  distribution   of, 
125 
excretion  in  disease,  127 
in  fever,  019 
in  hunger,  127 


Creatin-creatinin  metabolism,   125 
production,  kidney  in,  129 
liver  in,  129 
muscle   in,    128 
various  tissues  in.  129 
relations  of  tissue-protein  de- 
composition to,   120 
Crotonic   acid,   determination  of,   450 
in      formation      of      acetone 
bodies,    438,    405 
Curdling   of   milk,    bacterial    involve- 
ment in,  30 
Cutaneous  respiration,  590 
Cyanha?moglobin,   592 
Cyclic  nuclei,  disruption  of,  409 

oxidation  of,  408 
Cycknjoiesis,  497 
Cystein,  118,  475,  500 
Cystin,  118 
Cystinuria,    118.    119 
Cytase,  200 

D 

Darmstiidter's  method  of  quantitative 
determination    of    oxybutyric    acid, 
449 
Dead  and  living  protein,  509 
Deamidases.  70,  81,   149 
Deaminization,  81,  82,  471 

of  aminoacids,  82 
Degenerative  changes  in  living  body, 

autolysis  in,  85 
Depot  fat  and  cell-fat,  384 
Detoxification  by  glycuronic  acid  con- 
jugation, 319 
of    hydrocyanic   acid    by   thiosul- 
phates,  477 
phenols,    by    sulphuric    acid, 
sulphurous  acid,  persodin, 
etc.,  477 
by    sulphuric    acid    and    sulphur 
rests  in  body,  477 
Detoxifying  agents,  glycocoll  and  Orni- 
thin as,   112 
Dextrin  in  diabetes,  urinary,  207 
Dextrin-like  substances,  resorption  of, 

198 
Diabetes,  acidosis  in.  259 
adrenal,  300 

mechanism  of,  301 
pancreas  in,  310 
renal  influence  in,  302 
and  sugar  puncture,  304 
suppression  by  nephrotoxins, 
303 
agar-agar  in  diet  in,  271 
alcohol  in,  208 
aleuronat  in  diet  in,  271 
aminoacids  increased  in  urine  in, 

209 
cellulose  substituted  for  other  car- 
bohydrate  food   in,   200 


644 


INDEX 


Diabetes,  diet  in,  271 
duodenal,  250 
fat  catabolism  in,  269 
fatty,  269 
glandular,  278 
and     glucuronic    acid    excretion, 

Meyer's  theory  of,  320 
human,  263 

etiology  of,  263 

glycogen  of  liver  in,  265 

hyperglycemia  in,  266 

liver  in,  264 

pancreatic    degeneration    in, 

263 
and  pancreatic,  265 
Iceland  moss  in  diet  in,  271 
inulin  in  diet  in,  271 
lecithinaemia  in,  374 
lipogenic,    269 
medicinal  treatment  of,  272 
methylene-blue  reaction  of  blood 

in,  266 
mineral   water    in   treatment   of, 

272 
oatmeal  diet  in,  271,  442 
pancreatic,  247 

discovery  of,   247 

diastasic  power  of   liver  in, 

253 
glycogen   formation   in   liver 

in,  253 
metabolism  in,  258 
sugarjconsumption    in,    257, 

259 
sugar-elimination  in,  259 
sugar-formation  from  carbo- 
hydrate-free    material     in 
liver  in,  253 
symptoms  of,  249 
pentosuria  in,  289 
phloridzin,  275 

hyperglycemia  absent  in,  275 
kidney  in,  276 
mechanism   of,   280 
metabolism  in,  279 
sugar-formation  in  kidney  in, 
277 
protein-decomposition  in,  267,  269 
renal,   303 

respiration  experiments  in,  271 
respiratory  quotient  in,  242 
Röntgen  rays  in,  269 
substitutes  for  bread  in,  271 
urinary  dextrin  in,   267 
Diabetic  cholesterinaemia,  374 
coma,  440 

alkaline  treatment  of,  441 
and  acetone  bodies,  431 
lipaemia,  373 
economv,   oxidizing  processes   in, 

257 
lipaemia,    270,    373 
lipoidaemia,  373 


Diabetogenous  obesity,  270 
Diacetic  acid,  see  Aceto-acetic  acid 
Diacetyl  in  creatin  determination,  123 
Dialuric  acid  in  synthesis  of  uric  acid, 

156 
Diaminopropionic  acid,  deaminization 

of,  into  glyceric  acid,  471 
Diaminuria,  118 
Diastases,  augmentation  of,  220 

determination,    quantitative,    of, 

212 
in  embryos,  216 
hepatic,  214 
inactivation  of,  220 
isolation  of,  219 
muscle,  215 
origin  of,  216 
pancreas  in  production  of  blood-, 

217 
reactivation  of  inactive,  220 
starches,  various,  as  affected  by, 
219 
Diastasic  power  of  liver  in  pancreatic 

diabetes,  253 
Diazo-reaction,   145 
in  fever,  620 
and  histidin,  146 

imidoazol  compounds,   145 
oxyphenylacetic  acid,  145 
tyrosin,  145 
urochromogen,    139 
Diet  in  diabetes,  271 
gout,  192 
growth,  497 
lipaemia,  377 
in  obesity,  397 

use  of  protein-cleavage  products 
in  sickroom-,  66 
Dietary  allowance,  482 
Diethylmethylsulphinium     hydroxide, 

132,  476 
Diethylsulphide,  132,  476 
Digestion,   adaptation  of  enzvmes  to 
food,  196 
of  carbohydrates,  194 

fats,  350 
gases  of,  203 

gastric,    comparative    phvsiology 
of,  18 
of  living  tissues,  25 
of   proteins,    1 

extent  of,  15 
rapidity  of,  17 
intestinal,    of   proteins,   50 
products,   synthesis  of,  60 
resistance  of  aquatic  animals  to, 

26 
work  of,   529 
Diglycyl-glycin,    45 
Dimethylacrylic  acid  in  formation  of 

acetone  bodies,  438 
Dimethylguanidin,    133 


INDEX 


645 


Dioxyacetone,  461 

in      alcoholic      fermentation      of 
sugar,    346 
Disaccliarides,  assimilation  of,  229 
glycogen  formation  from,  229 
resorption  of,  197 
Dombrowski's  urochrome,  139 
Douglas'  respiration  apparatus,  518 
Dreser's  method  of  determining  HCl  in 

gastric  juice,  12 
Drugs,  various,  influencing  autolysis. 

90 
Ductless     glands     and     carbohydrate 
metabolism,   300 
see  also  Glands  with  internal 
secretion,       and       specific 
glands 
Duodenal  diabetes,  250 
Dynamic  effect  of  protein,  specific-,  529 
Dysoxidizable  substances  in  body,  535 
Dyszooamylia,  254 

E 

Echinochrom,  547 

Eckenstein  and  Blancksma  method  of 

acetone  determination,  448 
Eck's  fistula  animals,  intoxication  on 

meat  diet  in,  603 
Eck's  fistula  and  urinary  purin,  153 
Eclampsia,    increase    of    chondroitin- 
sulphuric    and    nucleinic    acids    in 
urine  in,   147 
Elastin,  adsorption  of  pepsin  by,  23 
failure  to  be  absorbed   from  in- 
testine, 55 
Electricity    increasing    hvdrolyzation 

of  starch,  220 
Electrolytic  cleavage  of  sugar,  343 
Electromotor  power  of  hydrogen   ion 
chains  of  gastric  juice,  measurement 
of,   in   estimating  acidity   of  juice, 
12 
Elevations,  see  Alpinism 
Embden's  schema  of  sugar  catabolism 
in  living  body,  460 
views  of  fat  catabolism  in  living 
body,  392 
Embryos,  diastases  in,  216 
Energv   computation    in   infant   feed- 
ing, 523 
exchange  in  alpinism.  607 

after  food  ingestion,   514 
and  surface  development,  522 
expense  in   fasting,   503 
law  of  conservation  of,   influenc- 
ing study  of  nutrition,  2 
law   of   constant   expenditure  of, 

525 
requirement  and  protein  require- 
ment, 486 
value  of  food.  Rubner's  standard 
figures  of,   52S 


Enterokinase,   41 

adsorption  by  fibrin  of,  42 
origin  of,  42 
Envelopment  of   sugar   in   colloids  of 

blood,  209 
Enzyme  carbohydrate-splitting,  211 

role  of  pancreas  in  pro- 
duction of,   196 
-duality,   219 
glycolytic,  256 

of  food  in  cellulose  digestion,  202 
Enzymic    catabolism    of    aminoacids, 

467 
Epiguanin,  167 
Epilogue,  634 
Eppinger-Falta  schema  of  interaction 

of  internal  secretory  glands,  313 
Eppinger-Falta  schema  of  interaction 

of  internal  secretory  glands,  Asher's 

modification  of,  316 
Erben's  method  of  oxyproteic  acid  de- 
termination, 144 
Erepsin,  50,  78,  79 
pancreatic,  43 
Erepsin  and  autolytic  tissue  ferments, 

51 
Erepsins,  tissue,  51,   76 
Ergotoxin,  263 

Erythrocytes,  sugar  content  of,  210 
Erythrodextrin,    196 
Esters,  cleavage  in  tissues  of,  403 
Ester-splitting  ferment  in  blood,  370, 

402 
Ethyl  alcohol  in  production  of  aceto- 

acetic  acid,  435 
Ethylbutyric    acid    in    production    of 

acetone  bodies,  438 
Ethylhydroperoxide,  540 
Ethylokrinin,  38 
Ethyl  sulphide,  476 
Excretion  coefficient  of  sugar.  Falta's, 

26S 


Falta's  excretion  coefficient  of  sugar, 

268 
Fasting,  acidosis  in,  505 

Batrachian  larvae  studies  in,  507 

blood  in,  501 

carbohydrate  metabolism  in,  504 

endurance  in,  499 

energy  expense  in,  503 

fat   covering   energy   expense    in, 

503 
fat   impoverishment   in,   503 
glycogen  formation  from  protein 

in,  505 
hibernation  studies  in,  506 
hunger  sensation  in,  507 
lipsemia  in,  504 
metabolism  in,  499 

total,  in,  501 
nitrogen  elimination  in,  503 


646 


INDEX 


Fasting,     nitrogen     metabolism     and 
minimal    nitrogen    metabolism 
in,  504 
protein  exchange  in,  503 
respiratory  quotient   in,  500 
Rhine  salmon,  studies  on,  in,  507 
urine  in,  505 
water  in,   504 
weight  loss  in,  500 
Fat   absorption,    parenteral,   379 
acetyl  figure  of,  385 
of  body  and  of  food,  relation  of 

acetone  bodies  to,  431 
from   carbohydrates,   characteris- 
tics of,  388 

place    of    formation    of, 
389 
catabolism    and    acetone    bodies, 
393 
in  animal  body,  392 
by  bacteria,  392 
Knoop's  theory  of,  433 
in  plants,  391 
cleavage  in  blood,  401 

intestine,      location      of, 
366 
in   absence   of   pan- 
creatic    secretion, 
366 
by      intestinal      microorgan- 
isms.  366 
and  solution  of  cleavage  prod- 
ucts, 352 
synthesis,    enzymic,    405 
of  coccygeal  gland,  427 
combined  in  protein  in  blood,  371 
decomposition  in  diabetes,  269 
depot,  and  cell.  384 
destruction  and  acidosis  in  fever, 

620 
digestion  and  absorption  of.   350 
influence  of  pancreatic  juice 

and   bile   upon,   359 
in  stomach,  350 
distribution  in  body,  380 
duodenal     reflux     into     stomach 

caused  by,   350 
of  embryo  chicks,  383 
emulsification  by  bile.  367 

influence    of    alkali    of    bile 
upon,  367 
energv  expense  in  fasting  covered 

by,"  503 
feeding,  fat-splitting  in  blood  in- 
fluenced by,  402 
feeding,   parenteral,   380 
of  food. milk-fat  derived  from, 424 
foreign,  assimilation  of,  381 

deposit  of,   381 
formation      from      carbohydrate, 
chemistry  of,  390 
protein,   405 

adipocere,  414 


Fat  formation  from  protein,  bacteria 
in,  410 
Hoffman's    fly   mag- 
got      experiment, 
413 
ripening    of    cheese, 
415 
in  kidney,  420 
from  sugar,  386 
form  of  hamiic,  367 
and     glycogen,     antagonism     be- 
tween, 373,  380 
from  glycogen,  place  of  formation 

of,  389 
impoverishment  from  phloridzin, 
243 
in  fasting,  503 
of  infants  on  natural  and  artificial 

food,  383 
infusoria  capable  of  digesting,  403 
inhibiting  gastric  secretion,  8 
iodized  and  bromized,  deposit  of, 

381 
liver  as  site  of  storage  of  avail- 
able,  386 
masking  in  blood,   370 

and   fatty   degeneration,   371 
metabolism,  378 

in  phloridzin  diabetes,  279 
theory    of    pancreatic    influ- 
ence upon,  361 
migration  of,  in  certain  fish,  376 
of  milk,  origin  of,  423 

origin  of,  from  carbohy- 
drates of   food,   425 
origin  of,  from  food  fat, 
424 
mobilization  and  lipamiia,  372 
nonsaponifiable,    behavior    in    in- 
testine, 354 
parenteral  resorption  of,  379 

feeding  with,   513 
passage  of,  from  blood  into  urine, 
375 
from  blood  stream,  375 
through  placenta,  376 
phanerosis   in  autolysis,  409 
and   fat   mobilization,   419 
in  fatty  degeneration,  418 
nature  of,  412 
protein  combination  in  blood,  371 

separation  of,  371 
resorption,  exclusion  of  pancreas 
affecting,   361 
by  intestine,  rapidity  of  re- 
sorption   of.    358 
in  intestine.  351 

histological      obser- 
vations on,  355 
path  of.  368 
respiration    experiments    on   con- 
version  of  carbohydrates   into, 
3S7 


INDEX 


C47 


Fat  of  sebaceous  glands,  427 

separation  from  protein  combina- 
tion of,  371 
of  species  and  races,  388 
-splitting    tissue    ferments,    401, 

405 
stained,  behavior  in  intestine  as 

to  resorbability,  359 
in  stool,  3G0 
storage  in  body,  380 
sugar  formation  from,  240,  241 

in  plants,  246 
supply    and    protein   destruction, 

378' 
synthesis  in  intestinal  wall,  353 
bv  reversal  of  action  of  lipase, 
*  365 
transformation  in  body.  382 

into  carbohydrate  in  plants, 
387 
types    met    in    various    animals 

from  types  of  food,  382 
utilization  as  influenced  by  arti- 
ficial   use   of    pancreatic    juice 
and  bile,  360 
Fattening,  398 

alcohol  in,  400 

from  carbohydrate  feeding,  399 
fat  feedmg.  400 
proteid  feeding,  399 
Fatty  acids,  acetone  bodies  from  lower, 
with    even    carbon    chains, 
432 
and  aliphatic  side  chains,  de- 
composition of,  464 
combination  with  aminoacids, 

412 
disintegration  of  long  chains 

into  short  chains  of,  434 
formation     by     microorgan- 
isms of  higher.  413 
Knoop's  theory  of  catabolism 

of  aliphatic,  392 
liver  in  oxidizing  higher,  385 
in  milk,  lower.  426 
route  from  carbohydrates  to. 

447 
solvent   power   of  bile   upon. 

367 
sugar  formation  and,  243 
degeneration,  distribution  of,  419 
and  fatty  infiltration,  406 
fatty   infiltration  in,  416 
and  fat  masking,  371 
and  fat  phanerosis,  418 
of  kidney,  419 
and  lactic  acid  accumulation 

in  blood,  371 
of  liver  in  phosphorus  poison- 
ing. 415 
Rosenfeld's     experiment     in. 

416 
Rosenfeld's  theory  of,  417 
diabetes,  269 


Fatty   infiltration  of  kidney,  420 

of  liver  in  phosphorus  poison- 
ing, 415 
and  fat  mobilization,  419 
and  fat  phanerosis,  419 
in   various  pathological  con- 
ditions, 417 
Feeding  with  carbohydrate  in  fatten- 
ing, 399 
fat,  400 
protein,   399 
Feeding,  parenteral,  508 

with  carbohydrate,  511 
with  fat,  379,  513 
with  protein  and  protein  de- 
rivatives, 62,  508 
danger  of,  510 
Fehling's  method  of  sugar  estimation, 

206 
Ferment-character  of  peroxidases,  548 
Ferment-cleavage  and  synthesis  of  fat 

by  lipase,  406 
Ferment,   fat-splitting   gastric,   350 

pancreatic,  359 
Ferments,  carbohydrate-splitting,  211 
fat-splitting  tissue,  401,  405 
glycolytic,   250 
tissue,  334 
nature  of,  21 
oxidizing,  534 
peptolytic,  75,  95 
proteolytic  gastric,  20 
pancreatic,  41 
tissue,   75,  91,  218 
detection  of,  92 
in  purin  metabolism,  149 
thermolabile     and     thermostable, 
553 
Fermentation,   law  of  peptic,   22 
tryptic,  47 
method  of  sugar  estimation,  206 
Fetal  lipoemia,  376 
Fever,  610 

acidosis   and   fat    destruction   in, 

620 
albumoses  in  urine  in,  620 
ammonia  elimination  in,  102,  620 
anthrachinone  producing,  632 
blood   plasma   changes   in,   622 
carbohydrate  metabolism  in,  621 
chlorine  retention  in,  624 
chondroitin-sulphuric      and      nu- 

cleinic  acids  in  urine  in,  147 
from  corpuscular  elements  intro- 
duced into  blood  in,  630 
creatin-creatinin  elimination,  619 
diazoreaction  in,  620 
frugality  of  economy  in,  614 
globulinsemia   in,   622 
and  glycogen,  225 
heat  elimination  decreased  in,  615 
production  in,  611 
regulating  centres,  increased 
excitability  of,  630 


648 


INDEX 


Fever,   heat   regulation,    by    chemical 
and  physical  means  in, 
626 
fixation    of,     at    higher 

grade,  628 
by  nervous  system,  C27 
hyperinosis  in,  622 
metabolic  velocity  in,  612 
metabolism,  total  in,  610 
muscular  activity  influencing  heat 

production,  611 
nitrogen  elimination  in,  616 

end-products,  elimination  of, 
619 
oxygen  capacity  of  blood  in,  589 
oxyproteic  acids  in  urine,  620 
protein  destruction  in,  616 

limited  by  carbohydrate 
food  in,  618 
from  purins,  632 
and  purin,  urinary,    153 
pyrogenic    property    of    proteins 

and  protein-derivatives,  630 
pyrogenesis  from  chemically  defi- 
nite  substances,  632 
reducing  power  of  tissues  in,  615 
resorption,  86 
R.  V.  T.  rule  in,  612 
respiratory  quotient   in,   614 
salt,   633 

significance  of,  633 
sugar,  633 
swelling    of    cellular    protoplasm 

in,  624 
toxogenic  influences  in  protein  de- 
struction in,  618 
uric   acid  eliminations   in,   619 
water  economy  in,  623 
retention  in,  623 
Fibrin,  glycolytic  ferment  in,  340 
Fish,   gastric   digestion   in,    19 
migration  of  fat  in,  376 
oxygen  secretion  in  swim-bladdei 
of,   596 
Fistula,  gastric,  3 

of  oesophagus,  Pawlow's,  3 
pancreas,  35 
Fistulous  dog,  poly-,  70 
Fly-maggot  experiment  of  Hoffman  in 
formation  of  fat  from  protein,  413 
Folin's  method  of  estimation  of  crea 

tinin,  122 
Folin   and   Schaffer"s   method  of  uric 

acid  estimation,  168 
Folin's  method  of  urea  estimation,  106 
Folin's  method  of  hippuric  acid  esti 

mation,    114 
Food,  adaptation  of  pancreatic  secre- 
tion to,  46 
amount  required,  482 

calory     computation     in     in- 
fants,  523 


Food,  cleavage  products  in  nutritional 
experiments,   496 
and  climate,  487 
elementary,  495 
ingestion,  energy  exchange  after, 

514 
metabolic    increase    after    inges- 
tion of,   529 
requirements,  482 
simple  substances  as,  495 
as  stimulus  to  gastric  secretion, 

6 
Tigerstedt's   formula   for   metab- 
olic  equilibrium   from,   527 
utilization  value  of,   527 
value,  Rubner's  standard  figures 

of,  482,  528 
withdrawal  of,  499 
Formaldehyde  in  electrolytic  cleavage 
of  glucose,  344 
glycogen    formation   from,    231 
Formic   acid   in   electrolytic  cleavage 
of  glucose,  344 
fermentative   glucose 
catabolism,  348 
oxidation    test    for    peroxi- 
dases, 540 
Formol    titration    method    of    amino- 

acid  determination,  119 
Freighting-theory    of    pancreatic    ac- 
tivity, 43 
Fructose,   241 
Fructose,    glycogen    formation    from, 

227 
Fuld's   method  of  pepsin  estimation, 

21 
Furfuracrylic  acid,  474 
Furfurol,  474 
Furfurol  reactions,  324 
v.    Fürth    and    Charnass    method    of 
lactic  acid  quantitative  determina- 
tion, 452 
V.    Fürth    and    Charnass    method    of 
lactic  acid  quantitative  determina- 
tion,    improvements     by     Embden 
laboratory,  454 

G 

Galactose  and  arabinose,  291 

assimilation  in  diabetes,  228 

limit  of,  228 
availability  of,  in  economy,  286 
glycogen  formation  from,  227 
Galactosuria,   alimentary,   in   hepatic 

disturbances,   286 
Gas  analysis  of  blood,  Barcroft  and 
Haldane    method, 
572 
technic    of,    584 
exchange  of  heart,  575 
intestine,   577 
liver    and    kidneys,    576 


INDEX 


64$ 


Gas  exchange  in  lungs,  579,  595 

methods  of  study  of,  514 
in  muscle,  574 

nervous  tissue,   575 
salivary  glands,  576 
Gases  of  blood,  579 
Gastrectomy,  19 

Gastric    contents,    binding    of    hydro- 
chloric    acid     by     protein 
bodies  in,  14 
passage  into  intestine  of,  33 
deficiency  in  certain  fish,  18 
digestion  in  amphibia,  17,  19 

comparative    physiology    of, 

18 
preparatory  to  tryptic  diges- 
tion, 17 
of  proteins,  1 

extent  of,  15 
velocity  of,  16 
fistula,  3 
secretin,  8 
secretion,  7,  8 

acid   determination   in,    12 
inhibition  of,  8 
mechanical  stimuli  to,  6 
nervous  mechanism  of,  4 
psychic  influences  upon,  5 
and  salivary  glands,  7 
stimuli  to,  6 
ulcer,  26 
Gelatine,  nutritive  value  of,   70 
Ginsburg's  method  of  oxyproteic  acid 

determination,   143 
Glands  of  internal  secretion  and  car- 
bohydrate   metab- 
olism,   300 
interrelation  of.  312- 
316 
Gland,    mammary,    phloridzin    influ- 
encing,  279 
salivary  submaxillary,  sugar  pro- 
duced by,  under  nervous  stimu- 
lation, 278 
thyroid,  removal  of,  311 

in   relation   to   carbohydrate 

metabolism,  311 
interrelation   with   other   in- 
ternal    secretory     glands, 
312-316 
Glandular  diabetes,  278 
Gliadin,  493-495 
Globulinremia  in  fever,  622 
Glucase  in  blood- serum,  218 
Glucese  in  blood-serum,  218 
Gluconic  acid,  258 

in    electrolytic    cleavage    of 
glucose,  344 
Glucosamine,   233,   234,   258 
in  blood,  209 

glycogen  formation  in  relation  to, 
230 


Glucose,  196 

alcoholic  fermentation  of,  345 
assimilation  limit  of,   228 

lowered  by  hyperthyroidism, 
312 
removal     of     para- 
thyroids, 311 
in  blood,  205 

catabolism  of,  Wohl's  schema,  345 
into  lactic,  acetic,  formic  and 
carbonic  acids  in  blood,  339 
electrolytic  cleavage  of,  343 
estimation,   methods  of,  206 
fermentative  catabolism  of,  347 
formation  from  protein,  231 
glycogen    formation   from,   227 
lactic  acid  from,  458 
tolerance        and        hypophyseal 

obesity,  315 
transformation   of  lsevulose   into, 

282 
ultra-violet  rays  as  cleavage  agent 
of,  344 
Glucosides   in  blood,  208 
Glutaminic  acid,  493 

sugar  formation  from,  240 
Glutaric  acid,  antiketogenic  influence 
of,  443 
preventing  phloridzin  glyco- 
suria, 281 
Glutinase,  43 
Glyceric   acid   deaminization   product 

of  diaminopropionic  acid,  471 
Glycerinaldehyde,  231 

in  glucose  catabolism,  345 
as  lactic  acid  producer,  400 
intermediate  product  in 
sugar  catabolism,  460 
Glycerol,  acetone  bodies  from,  439 
steatosis,  422 
sugar  formation  from,  240 
Glycocholic  acid,  113 

and  taurocholic  acid  salts  in 
activation  of  steapsin,  363 
Glycocoll,  64,  93,  108,  115 

and  benzoic  acid  in  formation  of 

hippuric  acid,  107 
detoxifying  influence  of,  112 
and  Ornithin,  conjugation  of  ben- 
zoic acid  with,  478 
sugar  formation  from,  240 
synthesis  of,  from  acetic  acid  and 
ammonia,    111 
Glycogen,  221 

in  blood,  209 
chemistry  of,  222 
consumption  of,  225 
content   of   liver   in    human    dia- 
betes, 265 
crystalline,  222 

detection  of,  microchemical,  223 
determination,    quantitative,    of, 
221 


650 


INDEX 


Glycogen,     determination,     quantitive 
of,  Pflügers'  method  of,  221 
disappearance  from  liver  in  use  by 
muscle,    224 
in  adrenal  diabetes, 
301 
in  diseases,   various,  225 
distribution   of,   224 
and  fat,  antagonism  between,  373 

380 
into  fat,  place  of  transformation 

of,  389 
formation  and  alcohol,  231 
from  cane-sugar,  229 
formaldehyde.   231 
glucose,   fructose,  galac- 
tose, 227 
and  glucosamine,  230 
in    liver,    in    pancreatic    dia- 
betes,   253 
perfused,    22G 
phloridzin    influenc- 
ing, 278 
from  maltose,  229 
pentose,  230 
protein  in  fasting,  505 
and  sugar  acids,  231 
hepatic,    226 

laevulose  in  formation  of,  228 
microchemical   identification,  223 
molecular  weight  of,  222 
muscle  demand  for,  224 
neoformation   of,   230 
physiology  of.  223 
protection    of,    against    catalysis, 

343 
removal  from  body  of,  224 
Glycogenic  function  of  liver,  disturb- 
ances of,  225 
Glycolaldehyde,  231 
Glycolysis,  327 

alkali  influencing,  341 
in  blood,   338 

blood-cells  in,  340 
Cohnheim's    pancreas-muscle    ex- 
periment in,  332 
views   of,   objections   to.    333 
in  diabetes,  255 
pancreas   in,  250,  332 
in   surviving  organs,  337 
Glycolytic   enzyme,   256 

theory,   objections   to.   333 
ferment  in  fibrin,  340 
muscle  ferment,  332 
tissue  ferments,  334 
Glyconeogenesis,  237 
Glycosuria  and  acromegaly,  314 

adrenal,    absence    of    thyroid    in- 
fluencing, 311 
relation  of  renal  function  to, 
302 
from  squeezing  adrenal  gland,  304 


Glycosuria,     alimentary,     absence     of 
thyroid   influencing,  311 
experimental,    of    various    types, 

295 
from  hypophyseal  extract,  314 
postoperative,  297 
refrigeration,  299 
renal.  295 
salt,  298 

from  sugar  puncture,  relation  of 
adrenal  to,  304 
sympathetic   nervous   excita- 
tion, 304 
thoracic  duct  fistula,  252 
toxic,  298 
Glycuronic  acid,  258,  288,  317 

conditions  of  conjugation  of, 

318 
conjugate,  317 

conversion  into  X-xylose,  321 
detection  and  estimation  of, 

323 
determination,     quantitative, 

of,  325 
excretion       and       diabetes, 
Meyer's  theory  of,  320 
in    respiratory    diseases, 
320 
in  diagnosis  of  diseases  of  in- 
testine and  liver,  322 
intoxications,  320 
occurrence  of,  in  body,  322 
origin  of,  from  sugar  oxida- 
tion, 319 
splitting  of  conjugate,  by  glu- 
coside-splitting      ferments, 
317 
Glycyl-alanin,  45 
Glycyl-glycin,  45,  93 
Glycyltryptophane  in  detection  of  pro- 
teolytic tissue  ferments,  92 
Glycyltyrosin  in  detection  of  proteoly- 
tic tissue  ferments,  92 
Glyoxylic  acid,   100-112 
Goldschmiedt's  reaction   in   intestinal 
diseases,  322 
test  for  glycuronic  acid,  325 
Gonorrheal  pus,  coloration  of  granules 
benzidin-monosulphite  of  soda,  542 
Gout,  170 

affinity  of  tissue  for  uric  acid  in, 

176' 
and  alcoholism,  186 
alkalinity  of  tissues  in  relation  to 
uric  acid  deposit  in  gout,   184 
and  chronic  lead  poisoning  in.  186 
curve    of   uric   acid   excretion    in 

acute  exacerbations  of,  174 
delayed     transformation    of    nu- 

cleins  in,  174 
experimentally  attempted,  185 
geographical  distribution  of,   187 
ffuanin,  150 


INDEX 


651 


Gout,  localization  of  uric  acid  deposi- 
tions in,  182 
meat  diet,  excessive,  influence  of, 

in,  1S7 
and  nephritis,  175 
plumbism,  18G 
production    of,    experimental    at- 
tempts, 1S5 
protracted  nucleinic  acid  feeding 

in,  187 
specitic  substances  in,   172 
tissue    alkalinity    influencing   de- 
posits in,  184 
treatment,  dietary,  of,  192 
medicinal,  of,  191 
radium  in,  188 
water,   alkaline,   in,   184 
uric  acid  curve  in  acute  exacerba- 
tions of.   174 
decomposition       reduced 

in,  173 
formation    increased    in, 

171 
in  blood  in,  170 
retention  in,  170 
solubility  of,   181 

in  alkalescence  vari- 
ations,  178 
complex     conditions 

of,  181 
nucleinic  acid  influ- 
encing, 180  • 
Gouty  tophi,  localization  of,  182 
Grate's   head    respiration    apparatus, 

518 
Gross'  method  of  trypsin  estimation. 

46 
Growth,  diet  in,  497 
laws  of,  524 

and  maintenance  metabolism,  514 
urinary  purin,   153 
Griitzner's    method    of    estimation   of 
pepsin,  21 
of  trypsin,  47 
Guaiac  reactions  with  peroxides,  53G 
Guaiaconic  acid  reactions.  537 
Guanase,  149 

lack   of.   in   economy  of  hog,   150 
Guanidin-acetic   acid,    131 

methylation   of,    in    pro- 
duction of  creatin,  131 
Guanin,  149 

conversion  into  uric  acid,  148 
gout  in   hog,   150 
Gunzberg's  method  of  acid  determina- 
tion  in  irastric  juice,  modifications 
of,  12 


H 


Ikemase,  556 
Humatin,  583 
Haematoporphyrin,  547 
Haemic  sugar.  205 


Hamioehrome,  581 
Hsemochromogen,  583 
Haemoconiosis,  369 
Hsemocyanin,  545,  547 
Haemerythrin,  547 
Haemoglobin,  579 

composition   of,   583 
crystallized,  579,  581 
individuality  of,  580,  581 
iron  in,  importance  of,  582 
molecular  weight  of,  582 
peroxidase-like  action  of,  543 
and    peroxidases,    differences    be- 
tween, 544 
oxygen  fixation  by,  Bohr  on,  591 
Henri  on,  591 
Hiifner's        formula 

for,  591 
Manchot    on,    591 
Ostwald  on,  592 
capacity     of,     physical- 
chemical      conception. 
590 
capacity   of,   salts   influ- 
encing, 590 
capacity  of,  temperature 
influencing,    589 
variability  of,  579 
Ha-moglobinometry,  Plesch's  improve- 
ment in,  586 
Haldane  and  Smith  method  of  blood 

gas  analysis,  585 
Hamster,  gastric  digestion  in,  20 
Hammersehlag's  method  of  estimating 

pepsin,  21 
Haptogenic  membranes  of  milk  glob- 
ules, 428 
Haskin's   method  of  urea  estimation, 

106 
Heart,  activity  in  alpinism,  602 

diastase  content  of  muscle  of,  216 

gas  exchange  of,  575 

and  lung  preparation  of  Starling. 

256,  340 
surviving,  glycolysis  in,  256,  337, 
340 
Heat  centre  of  brain,  627 

in    fever,    antipyretic    reduc- 
ing excitability  of,  630 
elimination  in  fever,  615 
producing  substances,  630 
production  of  anthrachinoide,  632 
chemically    definite    sub- 
stances, 632 
and      combustion     processes. 

610 
of    fever,    muscular    activity 

involved   in.   610 
and  glycogen,  225 
by   particulate   bodies   intro- 
duced  into  blood,  631 
protein,  specific-dynamic 
action  of.  in,  492,  529 


652 


INDEX 


Heat  production  by  purin,  632 

tetrahydronaphthyla- 
itiine,  G33 
regulation  in  fever,  chemical  and 
physical,  626 
fixation  of,  at  higher 
level,  628 
by  nervous  system,  627 
regulating  centres,   increased  ex- 
citability of,  630 
Hemielastin,  55 
Henri's     method     of     estimation     of 

trypsin,  46 
Henri  on  oxygen  fixation  by  haemoglo- 
bin,  591 
Henriques  and  Gammeltoft's  method 

of  urea  estimation,  107 
Henriques  and  Sörensen's  method  of 

hippuric  acid  estimation,  113 
Henriques  and  Sörensen's  method  of 

aminoacid  estimation,  120 
Hepatic  affections,  high  molecular  re- 
sidual substances  in  urine  in, 
147 
diastase,  214 

diseases,    loevulose    tolerance    de- 
creased in,  283 
functional  tests,  116,  129 
protagon,   410 
Heteroxanthin,  167 
Heubner  method  of  spectrophotometry 

of  blood,  586 
Hexahydrobenzoic    acid,    dehydration 

into  benzoic  acid,  469 
Hibernation,  metabolism  in,  117,  506 
Hippuric  acid,  107 

elimination  in  Carnivora  and 

man,  109 
estimation,  quantitative,  113 
formation   in   herbivora,   109 
His's  method  of  uric  acid  estimation, 

168 
Histidin  and  diazoreaction,  146 

in  construction  of  urochrome,  141 
Histozyme,  109 
Hoffman's  experiment  in  fat  formation 

from  protein  in  fly  larvae,  413 
Holmgren's    method    of    determining 

HCl  of  gastric  juice,  13 
Homogentisic  acid,  disruption  of,  470 
Hopkins'  method  of  uric  acid  estima- 
tion, 168 
Hormones  of  internal  secretory  glands, 

classification  of,  313 
Hryntschak's  method  of  hippuric  acid 

estimation,  114 
Hiifner  formula  for  oxygen  fixation  by 

haemoglobin,  591 
Human  diabetes,  263 
Hunger,  see  also  Fasting  and  Starva- 
tion 
metabolism  in,  499 
sensation  of,  507 


Hunger  and  thirst,  endurance  of,  499 
Hydrochinon,     hydroxylation    deriva- 
tive of  phenol,  468 
Hydrochloric  acid,  fixation  in  gastric 
contents    by    protein    sub- 
stances, 14 
ionic   theory    in   explanation 
of   formation   in   stomach, 
11 
origin  of  gastric,  9 
Hydrocyanic  acid,  98 

poisoning,    thiosulphates    in, 
477 
Hydrogen  and  nitrogen  in  metabolism, 

elemental,  520 
Hydroxylamine  method  of  sugar  esti- 
mation, 206 
Hydroxylaminoacetic  acid,   100 
Hyperinosis   in  fever,   622 
Hyperglycemia   in   diabetes,   266 

absence  of,  in  phloridzin  diabetes, 
275 
Hyperthermia,  see  Fever,  Heat 
Hyperthyroidism  and  diabetes,  312 
lowering  of  glucose  tolerance  by, 
312 
Hypoglycaemia    in    Addison's    disease, 

*306 
Hypophyseal  obesity,  316    _ 
Hypophysis,  relation  to  other  internal 
secretory  glands,  316 
extirpation  of,  suppressing  adre- 
nal glycosuria,  315 
glycosuria  from  extracts  of,  314 
relation  of,  to  carbohydrate  me- 
tabolism, 314 
Hypoxanthin,  149 


Iceland  moss  in  diabetic  diet,  271 

Imidazol   nucleus,    158 

Imidoazol  compounds  in  diazoreaction, 

145 
Imidoazolaininoacetic  acid,  146 
Imidoazolaminopropionic  acid,  146 
Imino-allantoin,   165 
Immunity    against    trypsin    parenter- 

ally  introduced,  48 
Inanition,  see  Fasting 
Indigo,  action  of  benzaldehyde  on,  534 
Indol.  hydroxylation  of,  into  indoxyl, 

468 
Indophenol  blue  injections,  551 
oxidases,   550 
synthesis,  550 
Indoxyl,      hydroxylation      derivative 

from  indol,  468 
Infant,   calory   computations   of   food 
for,  523 
energy  computation  in,  523 
fat  of  naturally  and   artificially 
fed,  383 


INDEX 


653 


Infant    feeding,    importance    of    food 
supply  of  nurse,  425 
glycuronic  acid  in  urine  of,  322 
lactosuria  in,  285 
Infectious     diseases,     autolysis     from 

toxins  of,  85 
Infusoria,  ability  to  digest  fats  by,  403 
importance    of,    in    digestion    of 
cellulose,  204 
Inosite,  458 

Intermediate  metabolism,  75 
Internal    secretion   of   pancreas,    con- 
viction    of,    by 
lymph,  252 
evidence  from  blood 
transfusion       and 
parabiosis,  252 
secretory  glands  and  carbohydrate 
metabolism,  300 
Eppinger-Falta     schema 

of  interrelation,  313 

Eppinger-Falta     schema 

of    interrelation,   Ash- 

ner's  modification,  316 

hormones    of,    classified, 

313 
interaction    of,    312 
specific  and  indirect  ef- 
fects of  removal  of,  312 
Intestinal  juice,  reflux  into  stomach 
of,  35 
loop  method  of  study  of  intestinal 

resorption  of  fats,  358 
respiration,  598 

villi,  Pavy's  theory  of  transforma- 
tion of  carbohvdrate  into  fat  bv, 
377 
Intestine,    absorption    of   products   of 
protein  cleavage  in,  53 
absorption    from,    influenced    by 

disease  ahd  by  age,  54 
carbohydrate  cleavage  in,  195 
chyme  into,  passage  of,  33 
digestion  of  proteins  in,  50 
digestion  of  proteins  in,  extent  of 

52 
fat  cleavage  in,  366 
gas  exchange  of,  577 
Goldschmiedt's  reaction  in  affec- 
tions of,  322 
glycuronic    acid    in    diagnosis   of 

affections  of,  322 
permeability  of  wall  of,  54 
proteins   and   protein   derivatives 
passing  through  the  wall  of,  54 
Intoxications  and  glycogen,  225 

glycuronic  acid  excretion,  320 
Introduction,  1 
Inulin  in  diet  of  diabetes.  271 

glycogen    formation   from,    230 
Invertase  in  blood  serum,  218 
Invertin  in  carbohvdrate  metabolism. 
195 


Iodine  method  of  determining  HCl  in 
gastric  juice,  13 
reaction  for  peroxidases,  539 
stimulating  autolysis,  91 
Iodized  fats,  deposit  of,  381 

proteins,   absorption  of,   57 
Iodoform  method  of  determination  of 

acetone,  448 
Ionic  theory  of  hydrochloric  acid  for- 
mation in  stomach,  11 
Iron,    importance    in    haemoglobin   of, 

547-583 
Islands  of  Langerhans  in  diabetes,  de- 
generation of,  263 
function  of,  249 
Isoamylalcohol,  467 
Isoamylamine,   467 

in  production  of  acetone  bodies. 
438 
Isobutyric  acid,  426 

intoxication,  434 
Isodynamics,  law  of,  529 
Isovaleraldehyde,    acetone    formation 

from,  438 
Isovalerianic  acid,  426 

acetone  formation  from,  438, 
467 


Jacoby's    method     of    estimation    of 

trypsin,  46 
Jaffe's  Creatinin  reaction,  123 
Jaundice  and  urinary  purin,  153 
Jecorin,  209,  410 
Jolles'  test  for  pentoses,  292 

K 

Karnitin,  133 

Ketonic    acids,     transformation     into 

aminoacids,  69 
Kidney  to  adrenal  diabetes,  relation 
of,  302 
chondroitin-sulphuric      and      nu- 
cleinic  acids  increased  in  urine 
in  diseases  of,  147 
and  creatin-creatinin   production. 

129 
fat  formation  in,  420 
fatty  degeneration  of,  419 

infiltration  of,  420 
impermeability  to  sugar,  normally 

of,  259 
and  liver,  gas  exchange  in,  576 
in  phloridzin  diabetes,  role  of,  276 
secretory    ability    of,    inhibition 
of    glycosuria    bv 
altering    the,    262 
peritoneal  irritation 
altering,  262 
sugar  formation  in  phloridzin  dia- 
betes in,  277 


654 


INDEX 


Kisch's  method  of  diastase  determina- 
tion, 213 
Knapp's  method  of  sugar  estimation, 

200 
Knoop's  theory  of  catabolism  of  ali- 
phatic fatty  acids,  3'J2 
decomposition   of   higher 

fatty  acids,  427,  404 
fat  catabolism,  433 
Kowarski's  method  of  uric  acid  esti- 
mation, 108 
Krüger  and  Schmid's  method  of  uric 

acid  estimation,  108 
Kumagawa-Suto's  method  of  sugar  es- 
timation, 200 


Lab-ferment,  14,  26 

separation     from     propepsin, 
23 
Lab-process,  bacterial  involvement  in, 
30 
physiological  purpose  of,  30 
ultramicroscopy  of,  29 
Laccase,  548 
Lactacidogen,  450 
Lactam  and  lactini  forms  of  urates, 

179 
Lactase  in  intestine,  195 
Lactation  and  lactosuria.  284 
Lactic  acid,  155,  239,  341,  452,  474 
and  autolysis,  457 
determination,        R  y  ft'  e  1 '  s 

method,  455 
in    fat    formation    from   car- 
bohydrate, 390 
f  a  t-p  r  o  t  e  i  n    combination, 
agency    in    separation    of, 
371 
fermentation      bv      lactolase 

328 
in  glucose  catabolism.  345 
fermentation,   348 
and  muscle  activity,  454 
and  muscle,  amount  of,  454 
and    oxybutyric   acid,    deter- 
mination  together   of,   455 
postmortem  formation  of,  456 
quantitative      determination 
by  v.  Fürth  and  Charnass 
method  of,  452 
quantitative      determination 
by  v.  Fürth  and  Charnass 
method    of,    improvements 
in,  by  Embden  laboratory, 
454 
production    from    glycerinal- 

dehyde  of.  400 
production  from  sugar  (race- 
mic    acid    as    intermediate 
product ) ,  462 
and  rigor  mortis,  459 


Lactic  acid,  sources  of,  456 

and    sugar,    interchange    of, 

401 
in  synthesis  of  uric  acid,  150 
urine,  402 
Lactokonids,  29 
Lactolase,  328 

Lactose,    fate    of    parenterallv    intro- 
duced, 197 
Lactosuria,  284 

in  childbed,  284 
infants,  285 
and  lactation,  284 
Lsevulose  in  amniotic  fluid  and  urine 
of  calves,  283 
assimilation  in  diabetes  of,  228 
detection  of,  281 
glycogen  formation  from,  228 
Seliwanoff's  test  for,  281 
tolerance   of,   lowered   in   hepatic 

disease,  283 
transformation    of    glucose    into, 
282 
La?vulosuria,  281 
alimentary,  283 
in  pregnancy,  283 
pure,  283 
urogenous.  282 
Langerhans,    degeneration    of    islands 
of,  in   human  diabetes.  203 
islands  of,  function  of,  249 
Lanolin,  unabsorbability   in  intestine 

of,  354 
Laurie  acid,   426 

Law  of  conservation   of  energy  influ- 
encing study  of  nutrition,  2 
constant       expenditure       o  f 

energy,  525 
growth,  524 
isodynamics.  529 
length  of  life,  Rubner's,  525 
peptic  fermentation,  22 
tryptic    fermentation.    47 
Lead  poisoning  and  gout,  chronic,  186 
Lecithin  as  activator  of  steapsin,  363 

in  blood   in  diabetes,  374 
Lefevre  and  Tollens'  determination  of 

glycuronic  acid,  325 
Leucin.  <il.  111,  467,  473 

acetone  bodies  from,  438 
benzoyl-,  111 
catabolism  of,  466 
sugar  formation  from,  239 
Leucocytes,  diastase  from,  216 

glycogenic  content  of,  in  diabetes, 

'254 
in  haemic  glycolysis,  339 
lipase  from,  403 
proteolytic  ferments  from,  S7 
Leucomalachite  green   method   of   de- 
tection   and    estimation    of    peroxi- 
dases,  541 


INDEX 


655 


Leucoprotease,  87,  88 

Leukaemia  and  urinary  purins,  153 

Liebig's   method    of   urea   estimation, 

106 
Life  in  cell  organization,  571 

Rubner*s  law  of  length  of,  525 
Lipaemia,  368 

and  acetone  bodies,  374,  432 

and  acidosis,  374,  432 

of  diabetes,  270,  373 

and  diabetic  coma,  373 

dietary,  377 

in  fasting.  504 

fetal,  376 

from  mobilization  of  fat  deposit, 

372 
and  narcosis,  374 
of  obese  alcoliolics,  377 
pathological.  372-374 
of  salmon,  373 
Lipase  of  blood,  401 

distinguished   from  pan- 
creatic  lipase,  402 
leucocytes,  403 
pancreas,  359 
reverse  ferment  action  of,  365 
of  stomach.  350 
tissue-activation  of,  404,  405 

character  of,  405 
vegetable,  406 
Lipogenic  diabetes,  260 
Lipoid,  importance  in  nutrition  of,  379 
essential  in  nutrition,  496 
solvent  power  of  bile  upon.  367 
steatosis,  422 
Lipoidaeniia  in  diabetes,  373 
Lipolytic   ferment   in   blood,   401 
of  pancreas.  359 
stomach,  350 
tissues,  403 
function  of  blood.  370 
Lipoproteids,  412 
Lipuria,  375 

Liver,  of  acute  yellow  atrophy,  autoly- 
sis in,  83 

ammonia      elimination      in      dis- 
eases of,  102 
and  creatin-creatinin  production, 

129 
in  chloroform  poisoning,  autolysis 

in,  84 
cirrhosis,  urinary  purin  in,  153 
in  diabetes,  human,  264 
diastase  of,  214 

blood  from,  218 
diastasic  power  in  pancreatic  dia- 
betes, 253 
exclusion  of,  101 
fat  storage  in,  386 
functional  tests  of,  116,  129,  280. 

323 
galactosuria,  alimentary,  in  affec- 
tions of,  286 


Liver,  glycogen  content  of,  in  human 
diabetes  in,  253 
and   diseases   of,   225 
formation  in  pancreatic  dia- 
betes in,  253 
perfused,  226 
phloridzin       influencing, 
278 
supply,  disappearance  of,  224 
glvcuronic    acid    in    diagnosis    of 

affections  of,  322 
and  kidney,  gas  exchange  of,  576 
oxidizing   function   of,    in    catab- 
olism  of  higher  fatty  acids,  385 
in  phosphorus  poisoning,  410 

fat  accumulation  in, 
415 
of  pregnancy,  417 
sugar     formation     in     pancreatic 
diabetes  from  carbohydrate-free 
material  in,  253 
sugar  puncture,  adrenin,  etc..  af- 
fecting diastase  of,  214 
urea  formation  in,  100,  101 
Living  and  dead  protein,  569 

tissues,  digestion,  in  stomach,  of, 
25 
London's  studies  upon  protein  diges- 
tion. 70 
Low's  active  protein,  569 
Ludwig  and  Salkowski  method  of  esti- 
mation of  uric  acid,  168 
Lungs,  extirpation,  partial,  of,  596 
gas  interchange  in.  579,  595 
oxygen  secretion  in,  596 
respiration   by,  594 
Lysin,  119 

M 

Maintenance  exchange,  502,  520 
metabolism  and  growth,  514 
Mammary  gland,  phloridzin  influenc- 
ing, 279 
Malonic  acid  in  uric  acid  synthesis, 

156 
Malta se.  229 

in  blood,   197,  218 
intestine,  195 
Maltose,  196 

assimilation   of,   229 
in  blood,  209 

glycogen  formation  from,  229 

parenterally   introduced,   197 

Man  an  exception  to  Rubner's  laws  of 

growth,  525 
Manchot  on  oxygen-fixation  by  haemo- 
globin, 591 
Mandelic  acid-esters,  406 
Manganese    as    catalyzing    agent    in 
sugar    catalysis,    343 
peroxide,  536 
Marsh-gas  fermentation   in   intestine, 
202 


656 


INDEX 


Mass  action,  592,  593 
Mastlipsemia,  377 
Meat  diet  in  gout,  excessive,  187 
Meat  reaction  in  urine,  135 
Medicinal  treatment  of  diabetes,  272 
Medulla  oblongata,  carbohydrate  regu- 
lating centre  in,  313 
Melanin,  141,  544,  554 
Melanin-like  products  in  urine,  141 
Melituria,  mixed,  282 
Mendel's  schema  of  creatin-creatinin 

elimination,  125 
Menstruation  and  creatin  metabolism, 

130 
Mercuric  cyanide  method  of  determin- 
ing acetone,  448 
Mercuric  cyanide  method  of  determin- 
ing sugar,  20b 
Mercury  stimulating  autolysis,  91 
Mesityl  oxide,  detoxification  by  sul- 

phydril,  478 
Messinger-Huppert  method  of  acetone 

determination,  448 
Metabolic     equilibrium,     Tigerstedt's 
formula  of,  527 
increase  after  food  ingestion,  529 

extent  of,  529 
minimum,  483 

nitrogenous   end-products,    elimi- 
nation in  fever  of,  619 
velocity  in  fever,  612 
Metabolism,  carbohydrate 

internal  secretory  glands  in, 

300 
regulation  by  adrenal,   304- 
309 
fat,  378 
in  fever,  610 
frugality     of     body     in     chronic 

febrile  conditions  in,  614 
intermediate,  75 

and  internal  secretory  glands,  316 
minimal,  483,  521 

in  alpinism,  607 
protein,   maintenance   by   protein 
derivatives,  72 
Metals,  colloid,  547.  548,  556 
Methamioglobin,  580,  583 

iron  in  fever  combination  in,  583 
Methane  in  intestine,  202 
Methylbutyric  acid,  439 
Methyl-glvoxal  in  glucose  catabolism, 

345 
Methyl-guanidin,  133 
Methyl-phenyl  hydrazine  osazone,  282 
Methyl-pyridylammon  him    hydroxide, 

132,  476 
Methyl-pyridin,  133 
Methylated  purin  derivatives,  166 
Methylation    process    in    metabolism, 

132 
Methylene  blue,  injections  of,  into  liv- 
ing tissue,  565 


Mett's  method  of  pepsin  estimation,  21 
Meyer's  theory  of  blood  glycolysis,  339 
Microorganisms  in  curdling  of  milk,  30 
intestinal  digestion  of  cellu- 
lose, 202 
formation    of    higher    fatty 
acids,  413 
Microrespirometer  of  Thunberg,  574 
Milk,  casein  of,  429 

curdling,     bacterial    involvement 
in,  30 
ultramicroscopy  of,  29 
lower  fatty  acids  in,  426 
modification  of  fats  from  food  of 

nurse,  424 
haptogenic  membrane  of,  428 
Milk-fat,   origin  of,  423 

from    carbohydrates    of 

food,  425 
from  fat  of  body,  424 
from  fat  of  food,  424 
Mineral  water  in  diabetes,  272 
gout,  179,  184 
obesity,  397 
Minimal  metabolism,  483,  521 

protein,  484 
"  Mock  feeding,"  3 
Monomethylxanthin,  167 
Monosaccharides,  resorption  of,  197 
Monte  Rosa  expeditions,  600 
Mörner-Sjöquist  method  of  urea  esti- 
mation, 106 
Mosso  Institute,  600 
Mountain  sickness,  see  Alpinism 
Mouse  cancers  and  treatment  by  col- 
loidal methods,  90 
Mucin,  233 

digesting  ferment  of  pancreas,  43 
Muconic    acid,    disruption    derivative 

from  benzol,  469 
Müller 's  method  of  determining  HCl 

of  gastric  juice,  12 
Muscular  activity  and  purin  metab- 
olism,  153 
Muscle  as  source  of  creatin,  128 
creatin  content  of,  128,  131 
diastase,  215 
gas  interchange  of,  574 
glycogen  in,  224 
glycolysis  in  surviving,  337 
glycolytic  ferment  in,  332-334 
hyaline  degeneration  of,  in  fever, 

617 
juice  and  pancreatic  extracts,  gly- 
colysis from,  332-334 
lactic  acid  in,  454 
Muscular  influence  on  heat  production 
in  fever,  611 
rest,  521 

tonic  contracture,  128 
Myelinosis,  422 


INDEX 


657 


Myeloid  cells,  absence  of  lipase  from, 

403 
Myristic  acid,  426 
Myxcedema,  311-316 

N 

Naphthaline,  hydroxylation  into  naph- 

thol,  468 
Naphthol,    hydroxy]    derivative   from 

naphthaline,  468 
Naphthoresorcin    test   for   glycuronic 

acid,  324 
Narcosis  and  lipaemia.  374 
Narcotics,  autolysis  from  the  cellular 

changes  from,  84 
Nationalities,  protein  requirements  of, 

486 
Nephritis   and    gout,    175 
Nephrotoxins  suppressing  adrenal  dia- 
betes,  303 
Nerve,    sympathetic    glycosuria    from 

irritation  of,  304 
Nervous   stimulation   of   chorda   tym- 
pani  and  sugar  of  submaxillary 
salivary  gland,  278 
mechanism  of  gastric  secretion,  4 
pancreatic   secretion,   36 
system    in    temperature    regula- 
tion, 627 
tissue,  gas  exchange  of,  575 

oxygen  requirements  of,  575 
Neuberg's  test  for  glycuronic  acid  in 

urine,  324 
Ninhydrin  reaction,  Abderhalden^,  96 
Nitrobenzaldehyde,  111 

reduction    to    acetylaminobenzoic 
acid,  471 
Nitrobenzol,  reduction  to  aminophenol, 

471 
Nitrogen  balance,  401 

and  protein  ingestion,  493 
elimination  in  fasting,  503 

fever,  616 
exchange  in  fasting  and  minimal 

nitrogen  metabolism,  504 
metabolism,  minimal,  504 
rest,  58 

retention  in  alpinism,  608 
urinary  rest-,  136 
and  hydrogen  as  element  in  me- 
tabolism, 520 
Nitrogenous  end-products,  elimination 

in  fever  of,  619 
Nitrophenylhydrazine   method   of   de- 
termining acetone,  448 
Novain,  133 
Nuclear     destruction      and     urinary 

purin,    152 
Nucleases,  76,  150 
Nucleins,    delayed    transformation    in 

gout  of.  174 
Nucleinases,  152 


Nucleinic  acid  in  urine,  147 

combination  of  uric  acid  in- 
fluencing solubility  of  uric 
acid,  180 
feeding  and  gout,  187 
parenterally  introduced,  fate 
of  in  mammals,  159 
Nucleosides,    151 
Nucleosid  deamidases,  152 
Nucleotids,  152 
Nucleotidases,  152 
Nurse,  importance  in  feeding  infants 

of  food  of,  424,  425 
Nutrition  on  diet  of  elementary  food- 
stuffs, 495 
parenteral,  508 
Nutritional  requirements,  482 

value  of  different  proteins,  493 

products  of  advanced 
protein  cleavage,  64, 
67 


Oatmeal  diet  in  diabetes,  271,  442 
Oats  starch,  action  of  diastase  on,  219 
Obesity,  378 

diabetogenous,  270 
gas  exchange  in,  394 
hypophyseal,  315 
metabolism  in,   394 
nature  of,  394 
and  overfeeding,  396 
thyroid  medication  in,  398 
treatment  of,  397 
Occupation  determining  food  require- 
ments, 483 
(Esophageal  fistula,  3 
Oil,  cod-liver,  389 

subcutaneous  introduction  of.  379 
test  breakfast,  35 
Orcin  test  for  glycuronic  acid  in  urine, 

324 
Organs,  Cohnheim's  respiration  appa- 
ratus for  isolated,  573 
methods  of  respiration,  study  of 
isolated,  571 
Ornithin,    118,  478 

detoxifying  influence  of,   112 
and  glycocoll,  conjugation  of  ben- 
zoic acid  with,  478 
Ornithuric  acid,  113,  478 
Osborne-Mendel  diet  in  rats,  496 
Ostwald  on  oxygen  fixation  by  haemo- 
globin, 592 
Ovary,  relation  to  internal  secretory 

glands,  316 
Overfeeding  and  obesity,  396 
Oxalic  acid  and  sugar  catabolism,  320 
originating  from  various  sub- 
stances. 321 
Oxaluria,  320 

Oxidase-like  action  of  haemoglobin  and 
iron,  547 


658 


INDEX 


Oxidases,  76,  534 
direct,  538 
indirect,  538 

in  purin  metabolism,  152 
and     respiratory     coloring     sub- 
stances, 547 
summary  of,  552 
Oxidation  of  fatty  acids  and  aliphatic 
side     chains,     Friedmann    and 
Dakin   schema  of,  4(54 
ferments,  534 
processes,  534 

processes  in  diabetic  economy,  257 
of  nitrogenous  substances,  vital, 

99 
and    reducing    powers    of    tissue, 
importance  of  sulphydril  to,  566 
Oxidizing  processes  in  diabetes,  257 
Oxyacridon,    oxidation    derivative   of 

acridin,  469 
Oxybutyria  acid,  431 

from  aldol,  391,  435 
and  aceto-acetic  acid,  reversi- 
bility of,  446 
bromine-crotonic  acid  method 
of  quantitative  determina- 
tion, 450 
catalytic   enzyme   action  on, 

447 
colorimetric    estimation     of, 

450 
Darmstädter's      method      o  f 
quantitative        determina- 
tion, 449 
in  diabetic  coma,  440 

determination,    quantitative, 

of,  449,  450 
from  fat  catabolism,  393 
in  febrile  urine,  620 

and  lactic  acid,  determination 

of,  together,  455 
in  normal   metabolism,   436, 

446 
polarimetry   of,   449 
Schaffer's  method  of  quanti- 
tative    determination     of, 
450 
from  shortening  of  long  fatty 

acid  chains,  439 
by    synthesis    from    tyrosin, 
439 
Oxygen  absorption,  invasion  and  eva- 
sion coefficients  of  blood,  587 
consumption  in  blood,  567 

measurement   of,    in   estima- 
tion of  peroxidases,  541 
fixation  capacity  of  blood,  influ- 
ence of  carbonic  acid  pressure 
on, 589 
fixation  capacity  of  blood,  influ- 
ence of  salts  on,  590 
fixation  capacity  of  blood,  influ- 
ence of  temperature  on,  589 


Oxygen    fixation    capacity    of    blood, 
maximum,  588 
fixation  capacity  of  blood,  physi- 
cal-chemical conception  of,  590 
fixation  by  haemoglobin,  591,  592 
requirement    of    nervous    tissue, 

575 
secretion,  596 

tension  curves  of  blood,  588 
Oxygenases,  536 
Oxyhemoglobin,  composition  of,  583 

peroxidase-like  action  of,  539,  543 
Oxyisovalerianic  acid  in  formation  of 

acetone  bodies,  438 
Oxyisophenylacetic  acid  in  diazoreac- 

tion,  145 
Oxyphenylacetic  acid,  145 
Oxyproteic  acid,  137 

elimination       and       sulphur 

elimination,  145 
elimination  of,  and  tissue  de- 
struction,  145 
fractionation  of,  137 
in   normal   and   pathological 

conditions,  144 
quantitative      determination 
of,  143 
Ozonization     of     corporeal     oxygen, 
S'chönbein's   theory   of,   534 


Panchymotic  dog,  70 
Pancreas,    activation   of    steapsin    by 
salts  of  biliary  acids,  363 
adaptation   to  cleavage  of  milk- 
sugar,  197 
in  adrenal  diabetes,  310 
adrenals  and  thyroid  interaction 

of,  313 
in  blood  glycolysis,  339 
carbohydrate    digestion    and    re- 
sorption, 196 
degeneration    of,    in   human   dia- 
betes, 263 
extirpation,   interrupted,   of,   248 
partial,  of,  260 
of,  section  of  cord  and  nerves 
influencing,  249 
in  fat  digestion,  359 
in  fat  metabolism,  theory  of  influ- 
ence of,  361 
in  glycolysis,  332 
internal  secretion  of,  252 
islands  of  Langerhans  of,  249 
renal  impermeability  to  sugar  in- 
fluenced by,  259 
role   of,    in   production   of  blood 
diastase,    217 
in     carbohydrate     digestion, 
195,   196 
mucin-splitting  ferment  of,  43 
peptone-splitting  ferment  of,  43 


INDEX 


659 


Pancreas,   proteolytic   ferment  of,   33 
relations    of,    to    other    internal 
secretory  glands,  316 
Pancreatic  activator  of  glycolytic  fer- 
ment, 332 
diabetes,  diastasic  power  of  liver 
in,  247 
discovery  of,  247 
glycogen  formation   in   liver 

in,  253 
metabolism    in,   258 
sugar  consumption  in,  259 
elimination  in,  259 
formation  from  carbohy- 
drate-free  material  in 
liver  in,  253 
digestion  of  proteids,  33 
erepsin,  43 
fistula,  35 
hormone,    261 

internal  secretion  activating  gly- 
colytic enzyme,  256 
juice,  influence  on  fat  digestion, 
359 
obtaining,  for  diagnostic  pur- 
poses, 35 
reflex  into  stomach  of,  35, 
proteolytic  fermentation,  law  of, 

47 
secretion,  activation  of,  41 
adaptation  to  foods  of,  46 
nervous  mechanism  of,  40 
stimuli  to,  36 

nervous,  to,  3B 
from  secretin,   37 
steapsin,  question  of  complexity 
of,  364 
Paraamidophenol,  hydroxy!  derivative 

from  aniline,  468 
Paracasein,  28 
Parachymosin,  28 

Paraffin,  non-absorbability  of,  in  in- 
testine, 354 
Parahaemoglobin,  580 
Parahydroxyphenylacetic  acid,  deriva- 
tion   of,    from    parahydroxyphenyl- 
ethylamine,  467 
Parasites  of  alimentary  canal,  resist- 

ence  of,  to  digestion,  24 
Parathyroids,     glucose     assimilation 
lowered  by  removal  of,  311 
relation  to  other  secretory  glands, 

316 
removal  of,  311 

and    thyroid,    differentiation    be- 
tween, 311 
Paraxanthin,  167 
Parenteral  absorption  of  fat,  379 
feeding  with  fat,  513 
introduction  of  protein,  62,  508 
dangers  of,  510 
protein    cleavage    prod- 
ucts, 510 


Parenteral  introduction  of  sugar,  511 
trypsin  toxicity  of,  48 
immunization 
against,  48 
Pavy's  theory  as  to  production  of  fat 
from    carbohydrate    by     intestinal 
villi,  377 
Pawlow's  method  of  diastase  estima- 
tion, 212 
Pawlow's  mock-feeding,  3 
oesophageal  fistula,  3 
pancreatic  fistula,  35 
ventriculus,  4 
Pentamethylene  diamine,   118 
Pentosans  in  plants,  288 
Pentoses,  detection  of,  292 

in  electrolytic  cleavage  of  glucose, 

344 
glycogen  formation  from,  230 
synthetic  production  of,  in  pento- 

surics,  291 
in  tissue  construction,  288 
vegetable,  in  metabolism  of  her- 
bivora,  289 
Pentosuria,  288 

alimentary,  289 
chronic,  290 
in  diabetes,  289 
Pepsin,  14,  20 

adsorption  by  elastin,  23 
determination,    quantitative,    of, 

21 
isolation  of,  20 
methods  of  estimation  of,  21 
passage  of,   into   intestine,  23 
and  rennin,  quality  of,  31 
separation  from  gastric  juice  by 
means  of  elastin,  23 
Peptic   digestion,   comparative,   19 

preparatory  to  tryptic  diges- 
tion, 17 
fermentation,   law  of,   22 
Peptoids  in  gastric  digestion,  16 
Peptolytic  power  of  blood-serum,  95 

tissue  ferments,  75 
Peptones,  action  of  erepsin  in,  16,  50 

sugar  formation  from,  237 
Peritoneal  irritation,  kidney  secretion 

altered  by,  261,  262 
Peroxidases,  536 
artificial,  547 
and   catalases,   559 
in  cells,  539 
detection     of,     by     oxidation     of 

formic  acid,  540 
doubt  as  to  ferment  character  of, 

548 
and    haemoglobin,    differences    be- 
tween, 544 
leucomalachite   green   method    of 
detection  and  quantitative  esti- 
mation, 541 


660 


INDEX 


Peroxidases,  limits  of  availability  of 
methods  of  estimation  of,  542 
measurement  of  oxygen  consump- 
tion in  estimation  of,  541 
purpurogallin    method    of    detec- 
tion, 540 
sources  of  error  in  study  of,  537 
Peroxidase-like  action  of  haemoglobin, 

539,  543 
Persodin  in  phenol  poisoning,  477 
Pettenkofer  type  of  respiration  appa- 
ratus, 514 
Pfliiger's  living  protein,  569 

method    of    glycogen    estimation, 

221 
on    fat    formation    from    protein, 

407 
on  sugar  formation  from  protein, 
233 
Pflüger-Bleibtreu-Schöndorf  method  of 

urea  estimation,  106 
Phenol,  derivation  from  benzol,  468 
detoxification  bv  sulphuric  acid  in 

body,  477 
hydroxvlation    into    hvdrochinon, 

468 
poisoning,  persodin  in,  477 
Phenol-glvcuronic    acid,    constitution 

of,  318 
Phenolphthalin    method    of    detecting 

peroxidases,  540 
Phenylacetic   acid,   478 
Phenylalanin,  108,  473 

catabolism  of,   467,   470 
in   production   of  acetone   bodies, 
439 
Phenylaminoacetic  acid,  475 
Phenylaminobutyric  acid,  475 
Phenylglyoxylic  acid,  475 
Phenylhydrazinsulphonic  acid  method 

of  sugar  estimation,  207 
Phenylpropionic  acid,   108,  112 

oxidation  of,  465 
Phenylpropionylglycocoll,  112 
Philocatalase,  561 
Philothian,  565 
Phloridzin,  275 

action  of,  on  mammary  gland?  27'» 
fat  impoverishment  from,  243 
fate  in  body  of,  280 
influencing  glycogen  formation  in 

liver,  278 
-diabetes,   275 

glutaric  acid  preventing  gly- 
cosuria of,  281 
hyperglycemia  absent  in,  275 
hypoglycemia  of,  275 
kidney  in,  276 
mechanism  of,  280 
metabolism  in,  279 
sugar  formation  in  kidney  in, 
277 


Phloroglucin  in  detection  of  glycuronic 

acid,  324 
Phorone,  detoxification  by  sulphydril, 

478 
Phosphates  in  sugar  catalysis,  342 
Phosphatids    of    tissue    as    reducing 

agents,  567 
Phosphoric  acid  in  alcoholic  fermenta- 
tion of  sugars,  347 
Phosphornucleases,   151 
Phosphorus    poisoning    and    acetone 
bodies,  432 
autolysis  in,  83 
fat  collection  in  liver  in,  415 
and  fat  phanerosis,  84 
hsemic  changes  in,  84 
liver  in,  84,  410 
and  urinary  purin,  153 
Phthalic  acid,  parenteral  introduction 

of,  468 
Picraminic    acid,    reduction    product 

of  picric  acid,  471 
Picric   acid,   reduction   to   picraminic 

acid,  471 
Pike's   Peak  expedition,   600 
Pilocarpin  stimulating  pancreatic  se- 
cretion, 41 
acting  on  glandular  activity  and 
urinary  purin,  153 
Placenta,  fat  passage  through,  376 
Plants,  fat  catabolism  in,  391 

sugar  formation  from  fat  in,  246 
Plasteins,  31 

possible  application  in   synthesis 
of    protein    digestive    products, 
61 
Plesch's  improvement  in  hemoglobin- 

ometry,  586 
Plumbism  and  gout,   186 
Pnein,  563 

Pneumonia,  chondroitin  -  sulphuric 
and  nucleinic  acids  in  urine  of,  147 
Pneumonic  and  other  exudates,  auto- 
lysis of,  85 
Polarimetrie  estimation  of  sugar,  206 
Polarimetry  of  oxybutyric  acid,  449 
Polyfistulous  dog,  70 

action  of  erepsin  on,  50 
Polypeptids,  tryptic  action  on,  45 

racemic,  splitting  of,  by  proteoly- 
tic ferments,  93 
Polysaccharides,   assimilation  of,  229 
fate  of,  in  alimentation,  197 
glycogen  formation  from,  229 
Potassium  as  catalytic  agent  in  sugar 

catalysis,  343 
Potato  starch,  diastase  acting  on,  219 
Pregnancy,  Abderhalden^  test  in,  96 

lsevulosuria  in,  283 
Prochymosin,  28 
Propepsin,  23 

separation   of,   from  lab-ferment, 
23 


INDEX 


661 


Prosecretin.  3S 

Protagon,  hepatic..  410 

Protamines  acted  on  by  arginase,  105 

Proteases,  78 

Protective  ferments  of  Abderhalden  in 

blood,  218 
Proteic  acid,  fractions  of,  138 
Proteid    substances    in    bodv,    variety 

of,  73 
Proteins,    absorption    from    intestine, 
54,  55 
of  iodized.  57 
ammonium  salts  in  synthesis  of, 

57 
carbohydrate  group  in,  233 
catabolism  in  metabolism,  velocity 

of,  498 
cleavage  products,  absorption  of, 
in  intestine,  53 
parenteral     introduction 

of,  510 
as     source     of     acetone 

bodies,  437 
value  of.  64 

value    of.    in    sick-room 
diet,   60 
constancy  of  tissue,  493 
construction     from     aminoacids, 

493 
derivatives  and  proteins  in  blood, 

54 
and  derivatives,   pyrogenic  prop- 
erties of,  630 
destruction  in  diabetes,  267-269 
in  fever,  616 

in    fever    limitation    of,    by 
carbohydrate  feeding,  618 
in  phloridzin  diabetes,  279 
sugar  elimination  in  relation 

to,  234 
supply  of  fat  influencing.  378 
digesting  tissue   ferments,   75 
digestion  and  assimilation,   sum- 
mary of,  72 
in  intestine,  50-52 
products,  synthesis  of,  60 
in  stomach,   15,  53 
economics   in   fasting,   503 
effects  of  excessive,  492 
exchange  in   fasting,   503 
extent  of  digestion  of,  in  stomach. 

15 
extent   of   digestion   of,   in   intes- 
tine, 52 
fat  production   from.  406 

adipocere,  414 
in    cheese    ripening, 
415 
Hoffman's   fly   larva   ex- 
periment. 413 

Pfliiger's    views    on, 
407 


Protein  feeding  with  products  of  ad- 
vanced cleavage  of,  64 
glucose  formation  from,  23 
in   heat   production,   492 
heterospecific     and    homospecific, 

493 
ingestion     of    heterospecific    and 

homologous.  494 
ingestion    and    nitrogen    balance, 

493 
living  and  dead,  569 
metabolism,   maintenance   of,    by 
protein   derivatives,   72 
stimulation  of,  by  urea  sub- 
cutaneously  introduced,  499 
minimal,   484 

pancreatic  digestion  of,  33 
parenterally   introduced,  62,  508 

danger  of,   510 
phvsiological   value   of   different, 

493 
requirement,  484 

in    different    tvpes    of    life- 
work,  486 
growing  child,  486 
low  limit  of.  488 
of  nationalities,  486 
and  total  energv  requirement, 
486 
specific   dvnamic   action   of,   492, 

529 
sugar  formation  from,  233,  238 

respiration     experi- 
ments upon,  236 
Weinland's     experi- 
ments on.  237 
surface  development  and  protein 

volume  of  body,  521 
svnthesis  from  ammonium   salts, 
67 
products      of      advanced 
protein  cleavage,  63 
tissue  and  circulating,   491 
of   plants,   mechanical    means   of 
utilization  of,  490 
Proteolysis,  inhibition  of,  by  products 

of  protein  cleavage,  94 
Proteolytic  ferments,  bacterial,  87 
classification  of,  94 
gastric,  20 
leucocytic,  87 
pancreatic,  41 
of  tissue.  75,  87 

Abderhalden'» 

studies  of,  91.  218 

detection  of,   87,  92 

detection  of,  by  gly- 

cyltyrosin,        silk 

peptone    and   gly- 

cyltryptophane,  92 

detection  of,  optical 

method.  92 


662 


INDEX 


Proteolytic  ferments  of  tissue,  optical 

determination  of,  92 
Protoplasmic    poisons    producing    al- 

lantoin,  159 
Pseudopepsin,  23 
Pseudoperoxidase,  544 
Psychic  influences  on  gastric  secretion, 
5 
secretion  of  stomach,  3 
Ptyalin,  194 

Puerperium,  lactosuria  of,  2S4 
Pulmonary    extirpation,    partial,    596 

respiration,  594 
Puncture,    sugar-.    296 
Purin  deamidases,  152 

decomposition  in  intestine,  164 
endogenous   and   exogenous,    148, 

152 
fate  of   parenterallv    introduced, 

162 
as  heat-producing  material,  632 
metabolism,  148 

enzymes  concerned  in,  149 
in    mammals,    allantoin    as 

end-product  of,  158 
and  muscular  activity,  153 
in  monkeys,  164 
pathology  of,  170 
methyl  derivatives  of,  166 
nucleases,  151 
nucleus,  157 
oxidases,  551 

synthetic  formation  of,  in  mam- 
mals, 157 
urinary,  in  disease,  153 

and  nuclear  destruction,  152 
Purpurogallin  method  of  detection  of 

peroxidases,  540 
Putrescin,    118 

Pylorus,  closure  of,  from  influence  of 
intestinal  contents,  34,  351 
influence  of  fat  upon,  351 
mechanism  of  action  of,  33 
Pyridin,  132,  476 
compounds,  133 

-leucomalachite  green  method  of 
blood  detection,  546 
Pyrimidine  nucleus,  157 
Pyrogenesis  from  chemically   definite 
substances.  632 
proteins  and  protein  deriva- 
tives, 630 
purins,  632 
Pyrogenic  substances,  631 
Pyromucic  acid.  478 
Pyroracemic  acid  in  glucose  metabol- 
ism, 345 

Q 

Quinic  acid,  dehydration  into  benzoic 
acid,  469 
emploved     in     treatment    of 
gout,  191 


Quinolin,     oxidation     into     quinolin- 

quinon,  469 
Quinolin    carboxylic    acids    in    gout 

treatment,  191 
Quinolin-quinon,  oxidation  derivative 

of  quinolin,  469 


Racemic  acid,  474 

intermediate       product       in 
catabolism     of     sugar     to 
lactic  acid,  462 
Radium  stimulating  autolysis,  91 
Radium  therapy  in  gout,  188 
Rectal   feeding   with   digestion   prod- 
ucts, 66 
Red  blood-cells,  sugar  content  of,  210 
Reducing  components  of  tissue,  565 
influence    of    tissue   phosphatids, 

567 
and  oxidizing  powers  of  tissues, 
importance    of    sulphydril    to, 
566 
power  of  tissues  in  fever,  615 
processes  in  body,  471 
Reductases,  565 

Reduction  methods  of  sugar  estima- 
tion, 206 
Reductonovain,  133 
Refrigeration  glycosuria,  299 
Regnault  and  Reiset  type  of  respira- 
tion apparatus,  515 
Renal  diabetes,  276,  303 

glycosurias,  295 
Rennet  ferment,  26 
Rennin  and  pepsin,  duality  of,  31 
Reptiles,  gastric  digestion  in,  19 
Resorption,  see  also  Absorption 

of  carbohydrate  products  from  in- 
testine, 197 
from  stomach,  17 
Respiration,    accessory,    563 
anaerobic,   329 

apparatus    for    aquatic    animals, 
519 
Benedict's  transportable,  518 
Douglas'  518 
Grafe's,  518 
for    isolated    organs,    Cohn- 

heim's,  572 
Pettenkofer's,   514 
Regnault  and  Reiset  type  of, 

515 
Rubner's  519 
for  small  animals,  518 
Thunberg's  microrespiro- 

meter,  574 
Zuntz  and  Geppert  type  of, 
517 
calorimeter,    Atwater   and   Bene- 
dict's, 516 


INDEX 


663 


Respiration  cardinal,  563 

changes  of,  in  alpinism,  603 
cutaneous,  596 

experiments  on  conversion  of  car- 
bohydrates into  fat,  387 
in  diabetes,  271 
intestinal,  598 
of    isolated    organs,    methods    of 

study  of,  571 
peritoneal,  598 
pulmonary,  594 
tissue,   563 
Respiratory  coloring  substances,  547 
diseases,    glycuronic    acid    excre- 
tion in,  320 
quotient  in  diabetes,  242 
fasting,  506 
fever,  614 
Rest,  grades  of,  521 
Rest,  nitrogen,  58 

urinary,   136 
R.  G.  T.  rule  in  fever,  612 
Robertson's  method  of  estimation  of 

trypsin,    46 
Röntgen   rays   in  diabetes   increasing 
glycosuria,  269 
and  urinary  purin,  153 
Rosenfeld's  experiment  as  to  source  of 
fat  in   liver  in  phosphorus  poison- 
ing, 416 
Rosenfeld's    theory    as    to    fatty    de- 
generation, 417 
Rubner's  calorimeter,  519 
laws  of  growth,  525 
law  of  length  of  life,  525 
standard  calory  figures  of  food, 
482,  528 
figures  of  food  value,  528 
Ruminants,   gastric    digestion    in,    20 
R.  V.  T.   rule  in  fever,   612 
Ryffer's  method  of  lactic  acid  deter- 
mination, 455 


Saccharic  acid,  258 

in    electrolytic    cleavage    of 
glucose,  344 
St.  Martin's  method  of  urea  estima- 
tion, 106 
Salaskin    and    Zalewski's    method    of 

urea  determination,   106 
Saliva,   action   of,   on   carbohydrates, 

194 
Salivary  glands,  gas  exchange  of,  576 
submaxillary,    sugar    in,    in 
nervous  stimulation,  278 
Salkowski's  urinary   colloids,    147 
Salmon,  fat  mobilization  in,  373 
inanition    studies   in,    507 
lipsemia  of,  373 
Salt  fever,  633 

Salts,  influence  of.  upon  oxygen  capac- 
ity of  blood,  590 


Sapokrinin,  38 

Saturation  limit  of  sugars,  232 

Schaffer's  method  of  oxybutyric  acid 

determination,  450 
Schütz-Borissow  law  of  peptic  fermen- 
tation, 22 
applied  to  trypsin,  47 
Sclerema  neonatorum,  383 
Sebaceous  glands,  fats  of,  427 
Secretin,  36,  37 

and  cholin,  differentiation  of,  39 
cholin  vasodilatin,  relations  of,  39 
gastric,  8 
Secretins,   multiplicity    of,    38 
Secretion,    gastric   inhibition   of,    8 
psychic  influences  upon,  5 
stimuli  to,  6 
of  oxygen,  596 
pancreatic,  37,  40 
Selen-methyl,  132,  476 
Seliwanoff's  test  for  lsevulose,  281 
Seromucoid,  56 

Serum,  peptolytic  power  of  blood-,  95 
and     blood-corpuscles,      carbonic 

acid  exchange,  594 
disease,  510 
Sick-room     diet,     advanced     protein- 
cleavage  products  in,  66 
Siegfried's  carbamino-reaction,  594 
Silk  peptone  in  detection  of  proteolytic 

tissue  ferments,  92 
Skin  of  infants,   fats  of,   383 

respiration,   596 
Sleep,  loss  of,  in  alpinism,  604 
Slosse's  schema  of  sugar  catabolism  in 

blood,  339 
van  Seyke's  method  of  aminoacid  de- 
termination, 120,  448 
Snails,  acid  production  by  marine,  12 
Soaps,  resorption  of,  in  intestine,  357 
Sodium  bisulphite  method  of  acetone 
determination,  448 
biurate,  178 

chloride  retention  in  fever,  624 
as   source   of  gastric  hydro- 
chloric acid,  9 
hemiurate,  178 
monourate,  178 
quadriurate,  178 
Solipeds,   gastric   digestion   in,   20 
Spectrophotometry  of  blood,  Heubner's 

method  of,  586 
Spleen,  freighting  theory  of  activation 

of  trypsin,  4.5 
Sprigg's  method  of  pepsin  estimation, 

21 
Starch,  action  of  diastase  on  various 
types  of,  219 
glycogen  formation  from,  230 
hydrolyzation    of,    increased    by 

electricity,  220 
hydrolyzation    of,    increased    by 
ultraviolet  rays,  220 


664 


INDEX 


Starvation,  see  also  Fasting 
and  acetone  bodies,  432 
endurance  of,   499 
influencing  fat  cleavage  in  blood, 

402 
metabolism  in,  501 
weight   loss   in,   500 
Steapsin,    activation    of,    by    biliary 
salts,  363 
question    of    complex    nature   of, 

364 
reactivation  of  inactive,  365 
reverse  ferment  action  of,  365 
Steatosis,  415,  422 

cholesterin-ester,  421 
Steenbock's  method   of   hippuric  acid 

estimation,  114 
Stereoisomeric  substances,  behavior  in 

body,  479 
Stereokinases,  480 

Stoklasa    on    zvmases    in   animal   tis- 
sues, 328 
Stomach,  acidity  of,  determination  of, 
12 
autodigestion  of,  resistance  to,  24 
bile  influencing  digestion  in,  197 
carbohydrate  cleavage  in,  195 
comparative  physiology   of.   19 
contents,  passage  of,  into   intes- 
tine, 33 
digestion  of  living  tissues  in,  25 
diverticulum  of  Pawlow's,  4 
extent  of  protein  digestion  in,  53 
extirpation  of,  18 
fistula  of,  3 

food  as  stimulus  to  secretion  of,  6 
hydrochloric  acid  of,  9 
hydrochloric  acid  of,  combined,  14 
hydrochloric  acid  of,  free,   12 
lipase  of,  350 
movements  of,  33 
nervous   mechanism   of    secretion 

of,  4 
passage    of    food    into    intestine 

from,  33 
passage     of     intestinal     contents 

into,  34 
protein  digestion  in,  1 
psvchic  influences  on  secretion  of, 

5 
rapidity  of  protein  digestion  in,  17 
resorption  in,  17 
secretion  of,  7 

inhibition  of,  8 
nervous  mechanism  of,  4 
psychic   influences,   3,   6 
and  salivary  glands,  7 
stimulation  of,  5,  6 
taste  influencing,  6 
ulcer  of,  26 

Pawlow's  ventriculus,  4 
Sucre  immediat  and  sucre  virtuelle  in 
blood,  208 


Sucre  virtuelle  and  glvcuronic   acid, 

322 
Sugar  acids  and  glycogen  formation, 
231 
in  aqueous  humor,  211 
in   blood,   estimation   of,   205 
in  blood-cells,  red,  210 
catabolism  from  alkali,  341 

in  blood,  Slosse's  schema  of, 

339 
glycerin-aldehyde     as     inter- 
mediate product  in,  460 
in     living     body,     Embden's 

schema  of,  460 
and  oxalic  acid,  320 
catalytic  agents  in  catabolism  of, 

342 
centre  near  hypophysis,  314 

in  medulla,  Bernard's,  225 
consumption    in    pancreatic    dia- 
betes, 257,  259 
destruction   in  economy,  327 
distribution  in  blood,  210 
electrolytic  cleavage  of.  343 
elimination,     relation     of     fatty 
acids  to,  243 
and  pancreatic  diabetes.  259 
and    protein    decomposition, 

234 
coefficient  of,  Falta's,  208 
envelopment  in  colloids  in  blood, 

209 
estimation,   methods   of,   200 
in   fat  formation,  386 
fever,   633 

formation,   from  alanin,  240 
from  aminoacids,  238,  239 
from  asparaginic  acid,  240 
from    carbohvdrate-free    ma- 
terial, 253* 
from  fat,  240 
from  fat  in  plants,  246 
from  fat,  D|N  quotient,  243 
and  higher  fatty  acids.  243 
from  glutaminic  acid,  240 
from  glycerol.  240 
from  glycocoll.  240 
in  kidney  in  phloridzin  dia- 
betes, 277 
from   leucin,   239 
from  peptone.  2:17 
protein,  233,  236,  237,  238 
free,  in  blood.  207 
incomplete  oxidation  of,  Meyer's 

theory,  320 
in    intestine,    dilution    of,    before 

resorption,   198 
and    lactic   acid,    interchange   of, 
461 

nitrogen  quotient   (D|N)   in  re 
origin  of  sugar  from  fat,  243 
origin    of    glucuronic    acid    from 
oxidation  of,  319 


INDEX 


665 


Sugar,  parenteral  feeding  with,  511 
puncture,  296 

and  adrenals,  304 

effect  of,  on  glycogen  in  liver, 

225 
effect  lost  after  exclusion  of 

adrenals,  305 
increase  of  adrenin  in  blood, 

307 
condition  of  adrenals  in,  306 
saturation  and  utilization,  limits 

of,  231 
as  source  of  lactic  acid,  458 
tolerance  in  hyperthyroidism,  312 
parathyroid  loss,  311 
hypophyseal  excess,  314 

loss,   315 
thyroid    deficiency,    311 
S'ulphanilic  acid,  98 
Sulphhamioglobin,    592 
Sulphur  elimination  in  protein  metab- 
olism, 498 
and  oxyproteic  acid  elimina- 
tion, 145 
Sulphur  rests  and  sulphur  compounds 
in  hydrocyanic  acid  poisoning,  477 
Sulphuric  acid  as  a  detoxifying  agent 

in  body,  477 
Sulphydril,  importance  in  relation  to 
autoxidizability  and  reducing  power 
of  tissue,  566 
Suppurative      processes,      proteolytic 
factor  in,  87 
antileueoprotease    treatment, 
88 
Suprarenal  and  Suprarenin,  see   Adre- 
nal and  Adrenin 
Surface  development   and   energy   ex- 
change, 522 
volume  of  bodv  protein, 
521 
tension  changes  in  study  of  lipoly- 
tic ferments.  404 
Sympathetic    nervous    stimulation    in 
production  of  glycosuria,  304 
sensitization   by  hypophysis   con- 
stituents, 315 
Sympathicotonia   and  glycosuria,  314 
Svnthesis  of  proteins,  ammonium  salts 
in,   67 
aminoacids  in.  63 
digestive  products,  60 


Tartronic   acid    in    synthesis   of   uric 

acid,  156 
Taurin,  98,  119,  470 
Taurocarbaminic  acid,  479 
Taurocholic  acid,  119 
Tellurmethyl,   132,  476 
Temperature   of   body,   see  also   Heat 
production,   Fever 


Temperature  increasing  the  metabolic 
velocity  in  fever,  612 
influencing    oxvgen    capacity    of 
blood,  589 
Teneriffe  expedition,   600 
Tension    curves   of   oxvgen   in   blood, 

588 
Tetracarbonimide,   165 
Tetraglycyl-glycin,  45 
Tetrahydronaphthylamine     in     pyro- 

genesis,  633 
Tetramethylamine   diamine,   118 
Theobromine,  167 
Theophyllin,   107 

Thiosufphates  in  detoxification  of  hy- 
drocyanic   acid,    477 
Thiourea,  476 

Thirst  and  hunger,  endurance  of,  499 
Thoracic  duct  fistula,  glycosuria  from, 

252 
Thunberg's  microrespirometer,  574 
Thyroid,   adrenals,   pancreas,   interac- 
tion of,  313 
gland    in   carbohydrate    metabol- 
ism, 311 
medication  in  obesity,  398 
and    parathyroids,    differen- 
tiation of,  311 
relation  of,  to  other  internal 

secretory  organs,  316 
removal  of,  311 
Tigerstedt's    formula     for    metabolic 

equilibrium,   527 
Tissue  affinity  for  uric  acid  in  gout, 
176 
enzymes.    75 

proteolytic,   75 
respiration,  563 
Tollen's  reaction  for  glvcuronic  acid, 

324 
Tophi,  localization  of  gouty,   182 
Toxicity   of  trypsin,  parenterally   in- 
troduced,  48 
parenterally    introduced, 
immunization  against, 
48 
Toxogenic    influences    in    the    protein 

destruction   of   fever,    618 
Trichlorethyl  alcohol,  reduction  prod- 
ucts of  chloral,  471 
Triglycyl-glycin,  45 
Trimethylamine,   134 

in    urine,    method    of    determina- 
tion, 134 
Trioxyglutaric     acid     in     electrolytic 

cleavage  of  glucose,  344 
Trypsin,  action  of,  on  Polypeptids.  45 
conversion  of,  into  zyrnoid,  44 
estimation,  quantitative,  of,  46 
fermentation  rule  of,  47 
immunization    against    parenter- 
ally introduced,  48 
individuality   of.   43 


666 


INDEX 


Trypsin  passage  of,  into  stomach,  23 
toxicity    of,    when    parenterally 

introduced,  48 
-zymogen,  41 
Trypsinogen,   41 

activation  of,  41,  42,  43 
Trypsoid,  44 
Tryptases,  76 
Tryptophane,  64,  497 
Tuberculosis,  urochromogen  and  diazo- 

reaction  in,  145 
Tyrosin,  64,  98,  145 

catabolism  of,  467,  470 
in    formation   of   acetone  bodies, 
439 
oxyphenyllactic  acid 
by  moulds,  472 
importance  of,  in  foods,  497 
reacting  with   diazo-bodies,    145 
Tyrosinase,  544,  548 

U 

Ulcer  of  stomach,  origin  of,  26 
Ultramicroscopy  of  lab-process,  29 
Ultra-violet     rays     causing    carbohy- 
drate cleavage,  344 
increasing  starch  hydrolyza- 
tion,  220 
Uraminoacids,  98,  478 
Urates,  lactam  and  lactim  forms  of, 
179 
solubility  of  different  urates  and 
uric  acid,   181 
Urea,  aminoacids  in  formation  of,  97, 
100 
ammonium   carbamate  in   forma- 
tion of,  97 
carbonate    in    formation    of, 
97,  100 
elimination  in   acidosis,   442 

postccenal,  105,  498 
estimation,  quantitative,  of,  106 
formation    in    body,    theories    of, 
97,   98,   99 
a     general    cellular 
function,   102 
liver  in,  100,  101 

perfusion       experiments 
in,  100 
place  of  formation   of,   in   bodv, 

101 
stimulating   protein   metabolism, 

499 
in  synthesis  of  uric  acid,  156 
Uiic  acid,  from  adrenin  and  guanin, 
149 
affinity  of  tissue  for,  in  gout, 

176 
alkali    combinations    of,    178 
and  allantoin,  158 
bacillus,    165 
curve   in   gout,    174 


Uric  acid,  decomposition  of,  reduced 
in  gout,  173 
diathesis,  182 

deposition  in  gout,   182,   184 
elimination  in  fever,  619 

leuka?mia,  153 
estimation    of,    quantitative, 

168 
excretion  in  acute  gouty  ex- 
acerbations,  174 
fate  of  intermediate,  in  mam- 
mals, 158 
in   man,    160 
orally      introduced, 

162,  164 
parenteral^     intro- 
duced,  159,  162 
fixed,  182 

formation  in  birds  and  rep- 
tiles, synthetic,  154 
formation   in  birds  and  rep- 
tiles,      oxidative, 
157 
gout,   171 
exogenous  and  endogen- 
ous, 148 
in    mammals,    oxidative, 
157 
increased   in   blood   in  gout, 

170 
influence  of  nucleinic  acid  in, 

180 
integrative  factor,  162 
loosely  combined,  182 
regeneration  of,  165 
retention  in  gout,  176 
solubilitv  in  relation  to  gout, 
179,   181 
in  variations  of  alkales- 
cence in  gout,   178 
synthesis,     absence     of,     in 
mammals,  157 

in  birds  and  reptiles,  154 
Uricsemia,  171 

endogenous,   171 
retention,  171 
Uricase,  161 

absence  in  human  tissues  of,  160 
Uricolysis,   158,   164 
in  monkeys,   164 
Urinary    colloids    of    Salkowski,    147 
dextrin  in  diabetes,  267 
purin,  origin  of  endogenous,  153 
rest,  nitrogen,  136 
Urine,  aromatic  substances  in,  319 
in  fasting,  505 
fat  from  blood  in,  375 
lactic  acid  in,  462 
removal  of  albumin  from.  206 
rest-nitrogen   in,   136 
Urocaninic   acid,    146 
Urochrome,   138 

chemical  status  of,   140 


INDEX 


667 


Urochronie.  Dombrowski's  139,  141 

true    (Weiss),    139,    141 

and  histidin,   141 

Weiss'  method  of  estimation,  139 
Urochromogen,  138 

in  cancer,   145 

and  diazoreaction,   139 

in  fever,   144,   620 
tuberculosis,    143 
Uroferric  acid,  147 
Uromelanin,   141 
Uropyrrol,  140 

Uterine  disturbances  and  creatin  me- 
tabolism,  130 
Utilization   limit  of  sugars,  232 

value  of  food,  527 


Vagus,  influence  of  section  on  hepatic 

diastase,  215 
Vasodilations,  secretin  and  cholin,  re- 
lations of,  39 
Vegetable  fibre,  digestion  of,  198 

food,   mechanical   preparation   of 
coarse,  490 
Vegetarianism,   485,   488 

amides  in  metabolism  in,  67 
Velocity  of  protein  catabolism,  498 
Ventriculus,  Pawlow's,  4 
Verworn's  biogen,  569 
Vital    oxidation    of   nitrogenous  sub- 
stances, 99 
processes,  534 
Vitiatin,   133 

Voit's   dietetic  allowance,   482 
Vollhard's  method  of  pepsin  estima- 
tion, 21 
modifications  of,  22 
rule  of  fermentation  applied  to 
pancreatic  digestion,  47 

W 

Wacker's     colorimetric     method      of 
sugar  estimation,  207 


Water,  alkaline  mineral,  in  treatment 
of  gout,  184 
mineral,  in  diabetes,  272 
economy  in  fever,  623 
in   fasting,   504 
retention   in   fever,   623 
withdrawal   of,    500 
Weight   in   fasting,   loss   of,   500 
Weiss'  method  of  estimation  of  uro- 
chrome  and  urochromogen,  139 
urochrome,   139 
Wiechowski's  method  of  allantoin  es- 
timation,   169 
of  hippuric  acid  estimation, 
114 
tissue-powder  method  of  diastase 
determination,  213 
Wohlgemuth's  method  of  diastase  de- 
termination, 212 
Work  in  alpinism,  capacity  for,  607 
Worms,   anoxybiotic  processes  in  in- 
testinal, 577 

X 

X-rays,  see  Röntgen  rays, 
Xanthin,   149 

fate   of   parenterally   introduced, 
164 
Xanthoxidases,    149 
Xylose,  288 

conversion  of  glvcuronic  acid  into, 
321 


Yeast  catabolism  of  aminoacids,  467 


Zein,  490,  495 

Zuntz   and  Geppert  type  of  respira- 
tion apparatus,  517 
Zymases    in    animal   tissue,    328 
vegetable  world,  327 
of  veast  and  alcoholic  fermenta- 
tion, 327 


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